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Sample records for small-field digital mammography

  1. Mammography

    MedlinePlus

    ... first test. TYPES OF MAMMOGRAPHY Traditional mammography uses film, similar to routine x-rays. Digital mammography is ... risk of dying of breast cancer compared to film mammography. Three-dimensional (3D) mammography is a type ...

  2. [Full-field digital mammography].

    PubMed

    Bick, U

    2000-12-01

    Due to the extremely high image quality requirements in mammography, there has for a long time been no adequate digital alternative to conventional film-screen mammography. The longest experience so far exists with digital mammography on the basis of storage phosphor (CR) systems. However, at normal dose this technique has a relatively poor signal-to-noise ratio and has not found general acceptance. Recently three novel systems for digital mammography by the companies Fischer (slot-scan detector), Trex (CCD-array), and GE (amorphous silicon detector) have been introduced and are currently under clinical investigation. The main advantage of digital mammography is the linear relationship between dose and detector signal with the possibility of a tailored optimization of image contrast. Other advantages include digital image storage, telemammography, and computer-assisted diagnosis.

  3. Digital Mammography and Digital Breast Tomosynthesis.

    PubMed

    Moseley, Tanya W

    2016-06-01

    Breast imaging technology has advanced significantly from the 1930s until the present. American women have a 1 in 8 chance of developing breast cancer. Mammography has been proven in multiple clinical trials to reduce breast cancer mortality. Although a mainstay of breast imaging and improved from film-screen mammography, digital mammography is not a perfect examination. Overlapping obscuring breast tissue limits mammographic interpretation. Breast digital tomosynthesis reduces and/or eliminates overlapping obscuring breast tissue. Although there are some disadvantages with digital breast tomosynthesis, this relatively lost-cost technology may be used effectively in the screening and diagnostic settings.

  4. Digital Mammography with Storage Phosphors

    DTIC Science & Technology

    1993-12-31

    of the data). Phanto imag Image quality of a mammographic unit is often checked with phantoms simulating a breast with the three major disease ...1981; 138:219-22. 28. Andersson I, Andren L, HildelU J, Linell F, Ljungqvist U, Pettersson H: Breast cancer screening with mammography. Radiology...breast scanner (CT/M) in diagnosis of breast diseases . Radiology 1979; 132:647-52. 47. Gisvold JJ,Karsell PR, Reese DF: Computerized tomographic

  5. Digital Mammography: Improvements in Breast Cancer Diagnostic

    NASA Astrophysics Data System (ADS)

    Montaño Zetina, Luis Manuel

    2006-01-01

    X-ray mammography is the most sensitive imaging technique for early detection of breast cancer (diagnostics). It is performed by a radiological system equipped with a rotating molybdenum (Mo) anode tube with an additional Mo filter. In the production of X-ray, bremsstrahlung photons produce an intense diffuse radiation, affecting the contrast between normal and cancerous tissue. So it is known that a good mammographic imaging can help to detect cancer in the first stages avoiding surgery, amputation or even death. In the last years there has been some developments in new imaging techniques to improve the contrast spatial resolution between different tissues: digital imaging, or the so call digital mammography. Digital mammographic imaging is considered an improvement in the prevention of breast cancer due to the advantages it offers.

  6. Digital Mammography: Improvements in Breast Cancer Diagnostic

    SciTech Connect

    Montano Zetina, Luis Manuel

    2006-01-06

    X-ray mammography is the most sensitive imaging technique for early detection of breast cancer (diagnostics). It is performed by a radiological system equipped with a rotating molybdenum (Mo) anode tube with an additional Mo filter. In the production of X-ray, bremsstrahlung photons produce an intense diffuse radiation, affecting the contrast between normal and cancerous tissue. So it is known that a good mammographic imaging can help to detect cancer in the first stages avoiding surgery, amputation or even death. In the last years there has been some developments in new imaging techniques to improve the contrast spatial resolution between different tissues: digital imaging, or the so call digital mammography. Digital mammographic imaging is considered an improvement in the prevention of breast cancer due to the advantages it offers.

  7. Discrepancies between film and digital mammography interpretations

    NASA Astrophysics Data System (ADS)

    Malhotra, Poonam; Kallergi, Maria; Alexander, Dominik; Berman, Claudia G.; Gardner, Mary; Hersh, Marla R.; Hooper, Lisa; Kim, Jihai J.; Venugopal, Priya

    2002-04-01

    The purpose of this study was to evaluate the frequency and reasons of disagreement between film and full-field digital mammography (FFDM) interpretations observed in a prospective clinical trial performed with the GE Senographe 2000D system. The data from 643 mammography examinations comprising both digital and film mammograms were analyzed for this purpose. Reports indicated that 455 findings were identified on the digital softcopy reading and 457 findings on the standard film mammography with 408 discrepancies. Findings with discrepancies were matched and analyzed. A reason was identified and a relative conspicuity score of 0 to 10 was assigned to each finding at the time of resolution; 0 corresponded to a finding highly conspicuous on digital, 10 to a finding highly conspicuous on film, and 5 denoted equal visibility on both. After review, agreement was established between the two modalities in 73.3% of the findings; 13.5% of findings were seen better on digital and 13.2% of the findings were seen better on film. Approximately 63% of the discrepancies occurred due to variability in the reporting style of the radiologists and/or unavailability of prior films for comparison. Three cancer cases were identified in this study; two were seen on both modalities and one only on film. In conclusion, no statistically significant differences were observed between digital and film mammography, a result that despite the small size of our dataset is in agreement with previous reports. Inter-observer variability, display differences, and presentation disagreements are the main reasons for interpretation differences that are primarily identified in the classification and BIRADS assignment.

  8. Digital mammography: physical principles and future applications.

    PubMed

    Gambaccini, Mauro; Baldelli, Paola

    2003-01-01

    Mammography is currently considered the best tool for the detection of breast cancer, pathology with a rate of incidence in constant increase. To produce the radiological picture a screen film combination is conventionally used. One of the inherent limitations of screen- film combination is the fact that the detection, display and storage processes are one and the same, making it impossible to separately optimize each stage. These limitations can be overcome with digital systems. In this work we evaluate the main characteristics of digital detectors available on the market and we compare the performance of digital and conventional systems. Digital mammography, due to the possibility to process images, offers many potential advantages, among these the possibility to introduce the dual-energy technique which employs the composition of two digital images obtained with two different energies to enhance the inherent contrast of pathologies by removing the uniform background. This technique was previously tested by using synchrotron monochromatic beam and a digital detector, and then the Senographe 2000D full-field digital system manufactured by GE Medical Systems. In this work we present preliminary results and the future applications of this technique.

  9. Optimization of Image Quality and Dose in Digital Mammography.

    PubMed

    Fausto, Agnes M F; Lopes, M C; de Sousa, M C; Furquim, Tânia A C; Mol, Anderson W; Velasco, Fermin G

    2017-04-01

    Nowadays, the optimization in digital mammography is one of the most important challenges in diagnostic radiology. The new digital technology has introduced additional elements to be considered in this scenario. A major goal of mammography is related to the detection of structures on the order of micrometers (μm) and the need to distinguish the different types of tissues, with very close density values. The diagnosis in mammography faces the difficulty that the breast tissues and pathological findings have very close linear attenuation coefficients within the energy range used in mammography. The aim of this study was to develop a methodology for optimizing exposure parameters of digital mammography based on a new Figure of Merit: FOM ≡ (IQFinv)(2)/AGD, considering the image quality and dose. The study was conducted using the digital mammography Senographe DS/GE, and CDMAM and TORMAM phantoms. The characterization of clinical practice, carried out in the mammography system under study, was performed considering different breast thicknesses, the technical parameters of exposure, and processing options of images used by the equipment's automatic exposure system. The results showed a difference between the values of the optimized parameters and those ones chosen by the automatic system of the mammography unit, specifically for small breast. The optimized exposure parameters showed better results than those obtained by the automatic system of the mammography, for the image quality parameters and its impact on detection of breast structures when analyzed by radiologists.

  10. Digital mammography, cancer screening: Factors important for image compression

    NASA Technical Reports Server (NTRS)

    Clarke, Laurence P.; Blaine, G. James; Doi, Kunio; Yaffe, Martin J.; Shtern, Faina; Brown, G. Stephen; Winfield, Daniel L.; Kallergi, Maria

    1993-01-01

    The use of digital mammography for breast cancer screening poses several novel problems such as development of digital sensors, computer assisted diagnosis (CAD) methods for image noise suppression, enhancement, and pattern recognition, compression algorithms for image storage, transmission, and remote diagnosis. X-ray digital mammography using novel direct digital detection schemes or film digitizers results in large data sets and, therefore, image compression methods will play a significant role in the image processing and analysis by CAD techniques. In view of the extensive compression required, the relative merit of 'virtually lossless' versus lossy methods should be determined. A brief overview is presented here of the developments of digital sensors, CAD, and compression methods currently proposed and tested for mammography. The objective of the NCI/NASA Working Group on Digital Mammography is to stimulate the interest of the image processing and compression scientific community for this medical application and identify possible dual use technologies within the NASA centers.

  11. Clinical Optimization of Current Digital Mammography Systems (Breast Cancer)

    DTIC Science & Technology

    1994-01-20

    AD-A280 249 ’ •) AD_______ GRANT NO: DAMD17-93-J-3008 TITLE: CLINICAL OPTIMIZATION OF CURRENT DIGITAL MAMMOGRAPHY SYSTEMS (BREAST CANCER ) PRINCIPAL...Current Digital Mammography Systems (Breast Cancer ) Grant No. 6 . _ _ _ _ _ _ __ D A M D 1 7 - 9 3 - J - 3 0 0 8 AUTH•OR(S) Matthew T. Freedman, M.D...will be continuing our research with a 42 micron film digitizer when a machine arrives at our site early in 1994. Breast Cancer , Mammography, Digital

  12. Digital mammography performed with computed radiography technology.

    PubMed

    Jouan, B

    1999-07-01

    Introduced by Fuji Photo Film Japan in the early 1980s, computed radiography (CR) technology has developed considerably since then to become the mature widely installed technology it is today (about 7500 systems worldwide). Various mammographic examinations require high performance results to which CR complies on demand or following some procedures such as geometrical magnification carried out during the examination. The basic CR principles and digital image processing as well as technical improvements are detailed in this study, which also includes a synthesis of the articles on CR mammographic applications referenced in the bibliography, focusing on strong points, limits and current methods of surpassing these limits. New CR technology development perspectives in mammography and computed assisted diagnosis (CAD) algorithms will allow wider use of this method in the near future.

  13. Contrast-Enhanced Digital Mammography and Angiogenesis

    SciTech Connect

    Rosado-Mendez, I.; Palma, B. A.; Villasenor, Y.; Benitez-Bribiesca, L.; Brandan, M. E.

    2007-11-26

    Angiogenesis could be a means for pouring contrast media around tumors. In this work, optimization of radiological parameters for contrast-enhanced subtraction techniques in mammography has been performed. A modification of Lemacks' analytical formalism was implemented to model the X-ray absorption in the breast with contrast medium and detection by a digital image receptor. Preliminary results of signal-to-noise ratio analysis show the advantage of subtracting two images taken at different energies, one prior and one posterior to the injection of contrast medium. Preliminary experimental results using a custom-made phantom have shown good agreement with calculations. A proposal is presented for the clinical application of the optimized technique, which aims at finding correlations between angiogenesis indicators and dynamic variables of contrast medium uptake.

  14. Triple-energy contrast enhanced digital mammography

    NASA Astrophysics Data System (ADS)

    Puong, Sylvie; Milioni de Carvalho, Pablo; Muller, Serge

    2010-04-01

    With the injection of iodine, Contrast Enhanced Digital Mammography (CEDM) provides functional information about breast tumour angiogenesis that can potentially help in cancer diagnosis. In order to generate iodine images in which the gray level is proportional to the iodine thickness, temporal and dual-energy approaches have already been considered. The dual-energy method offers the advantage of less patient motion artifacts and better comfort during the exam. However, this approach requires knowledge of the breast thickness at each pixel. Generally, as compression is applied, the breast thickness at each pixel is taken as the compression thickness. Nevertheless, in the breast border region, this assumption is not correct anymore and this causes inaccuracies in the iodine image. Triple-Energy CEDM could overcome these limitations by providing supplemental information in the form of a third image acquired with a different spectrum than the other two. This precludes the need of a priori knowledge of the breast thickness. Moreover, with Triple-Energy CEDM, breast thickness and glandularity maps could potentially be derived. In this study, we first focused on the method to recombine the three images in order to generate the iodine image, analyzing the performance of either quadratic, cubic or conic recombination functions. Then, we studied the optimal acquisition spectra in order to maximize the iodine SDNR in the recombined image for a given target total glandular dose. The concept of Triple-Energy CEDM was validated on simulated textured images and poly-energetic images acquired with a conventional X-ray mammography tube.

  15. Frequently Asked Questions about Digital Mammography

    MedlinePlus

    ... is a mammography system where the x-ray film used in screen-film mammography is replaced by solid-state detectors, similar ... on a computer screen, or printed on special films to look like screen-film mammograms. Types of ...

  16. Mammography

    MedlinePlus

    ... mammography facility. top of page What does the equipment look like? A mammography unit is a rectangular ... be notified of the results by the mammography facility. Follow-up examinations may be necessary, and your ...

  17. Quantification of breast arterial calcification using full field digital mammography.

    PubMed

    Molloi, Sabee; Xu, Tong; Ducote, Justin; Iribarren, Carlos

    2008-04-01

    Breast arterial calcification is commonly detected on some mammograms. Previous studies indicate that breast arterial calcification is evidence of general atherosclerotic vascular disease and it may be a useful marker of coronary artery disease. It can potentially be a useful tool for assessment of coronary artery disease in women since mammography is widely used as a screening tool for early detection of breast cancer. However, there are currently no available techniques for quantification of calcium mass using mammography. The purpose of this study was to determine whether it is possible to quantify breast arterial calcium mass using standard digital mammography. An anthropomorphic breast phantom along with a vessel calcification phantom was imaged using a full field digital mammography system. Densitometry was used to quantify calcium mass. A calcium calibration measurement was performed at each phantom thickness and beam energy. The known (K) and measured (M) calcium mass on 5 and 9 cm thickness phantoms were related by M=0.964K -0.288 mg (r=0.997 and SEE=0.878 mg) and M=1.004K+0.324 mg (r=0.994 and SEE = 1.32 mg), respectively. The results indicate that accurate calcium mass measurements can be made without correction for scatter glare as long as careful calcium calibration is made for each breast thickness. The results also indicate that composition variations and differences of approximately 1 cm between calibration phantom and breast thickness introduce only minimal error in calcium measurement. The uncertainty in magnification is expected to cause up to 5% and 15% error in calcium mass for 5 and 9 cm breast thicknesses, respectively. In conclusion, a densitometry technique for quantification of breast arterial calcium mass was validated using standard full field digital mammography. The results demonstrated the feasibility and potential utility of the densitometry technique for accurate quantification of breast arterial calcium mass using standard digital

  18. Quantification of breast arterial calcification using full field digital mammography

    PubMed Central

    Molloi, Sabee; Xu, Tong; Ducote, Justin; Iribarren, Carlos

    2008-01-01

    Breast arterial calcification is commonly detected on some mammograms. Previous studies indicate that breast arterial calcification is evidence of general atherosclerotic vascular disease and it may be a useful marker of coronary artery disease. It can potentially be a useful tool for assessment of coronary artery disease in women since mammography is widely used as a screening tool for early detection of breast cancer. However, there are currently no available techniques for quantification of calcium mass using mammography. The purpose of this study was to determine whether it is possible to quantify breast arterial calcium mass using standard digital mammography. An anthropomorphic breast phantom along with a vessel calcification phantom was imaged using a full field digital mammography system. Densitometry was used to quantify calcium mass. A calcium calibration measurement was performed at each phantom thickness and beam energy. The known (K) and measured (M) calcium mass on 5 and 9 cm thickness phantoms were related by M=0.964K−0.288 mg (r=0.997 and SEE=0.878 mg) and M=1.004K+0.324 mg (r=0.994 and SEE=1.32 mg), respectively. The results indicate that accurate calcium mass measurements can be made without correction for scatter glare as long as careful calcium calibration is made for each breast thickness. The results also indicate that composition variations and differences of approximately 1 cm between calibration phantom and breast thickness introduce only minimal error in calcium measurement. The uncertainty in magnification is expected to cause up to 5% and 15% error in calcium mass for 5 and 9 cm breast thicknesses, respectively. In conclusion, a densitometry technique for quantification of breast arterial calcium mass was validated using standard full field digital mammography. The results demonstrated the feasibility and potential utility of the densitometry technique for accurate quantification of breast arterial calcium mass using standard digital

  19. Quantification of breast arterial calcification using full field digital mammography

    SciTech Connect

    Molloi, Sabee; Xu Tong; Ducote, Justin; Iribarren, Carlos

    2008-04-15

    Breast arterial calcification is commonly detected on some mammograms. Previous studies indicate that breast arterial calcification is evidence of general atherosclerotic vascular disease and it may be a useful marker of coronary artery disease. It can potentially be a useful tool for assessment of coronary artery disease in women since mammography is widely used as a screening tool for early detection of breast cancer. However, there are currently no available techniques for quantification of calcium mass using mammography. The purpose of this study was to determine whether it is possible to quantify breast arterial calcium mass using standard digital mammography. An anthropomorphic breast phantom along with a vessel calcification phantom was imaged using a full field digital mammography system. Densitometry was used to quantify calcium mass. A calcium calibration measurement was performed at each phantom thickness and beam energy. The known (K) and measured (M) calcium mass on 5 and 9 cm thickness phantoms were related by M=0.964K-0.288 mg (r=0.997 and SEE=0.878 mg) and M=1.004K+0.324 mg (r=0.994 and SEE=1.32 mg), respectively. The results indicate that accurate calcium mass measurements can be made without correction for scatter glare as long as careful calcium calibration is made for each breast thickness. The results also indicate that composition variations and differences of approximately 1 cm between calibration phantom and breast thickness introduce only minimal error in calcium measurement. The uncertainty in magnification is expected to cause up to 5% and 15% error in calcium mass for 5 and 9 cm breast thicknesses, respectively. In conclusion, a densitometry technique for quantification of breast arterial calcium mass was validated using standard full field digital mammography. The results demonstrated the feasibility and potential utility of the densitometry technique for accurate quantification of breast arterial calcium mass using standard digital

  20. Technology evaluation center assessment synopsis: full-field digital mammography.

    PubMed

    Rothenberg, Barbara M; Ziegler, Kathleen M; Aronson, Naomi

    2006-08-01

    Full-field digital mammography (FFDM) is proposed as an alternative to screen-film mammography (SFM). The ability to separate and optimize the acquisition, storage, and display of images may allow greater visualization of breast cancers at equal or lower radiation doses, especially in younger women and those with denser breasts. This is a synopsis of a systematic review by the Blue Cross Blue Shield Association Technology Evaluation Center. This updated systematic review primarily incorporated the results of the ACR Imaging Network(R) Digital Mammographic Imaging Screening Trial (DMIST), which provided results on 42,760 asymptomatic women who underwent both FFDM and SFM and showed with reasonable certainty that there was no difference in the accuracy of the 2 modalities for asymptomatic women in general, with some advantages of FFDM in certain subgroups. There were no strong, new studies on the use of digital mammography compared with film mammography in a diagnostic population. However, the DMIST results indicated that tumors detected by FFDM, but not by SFM, were likely to be invasive carcinomas or medium-grade to high-grade ductal carcinoma in situ. On the basis of the suppositions that these are the cancers of greatest interest and the ones more likely to be found in a diagnostic population and that the diagnostic population may be younger on average than the screening population, it was concluded that there is sufficient evidence to support the use of FFDM for diagnostic purposes.

  1. LATIN AMERICAN IMAGE QUALITY SURVEY IN DIGITAL MAMMOGRAPHY STUDIES.

    PubMed

    Mora, Patricia; Khoury, Helen; Bitelli, Regina; Quintero, Ana Rosa; Garay, Fernando; Aguilar, Juan García; Gamarra, Mirtha; Ubeda, Carlos

    2016-03-23

    Under International Atomic Energy Agency regional programmeTSA3 Radiological Protection of Patients in Medical Exposures, Latin American countries evaluated the image quality and glandular doses for digital mammography equipment with the purpose of seeing the performance and compliance with international recommendations. Totally, 24 institutions participated from Brazil, Chile, Costa Rica, El Salvador, Mexico, Paraguay and Venezuela. Signal difference noise ratio results showed for CR poor compliance with tolerances; better results were obtained for full-field digital mammography equipment. Mean glandular dose results showed that the majority of units have values below the acceptable dose levels. This joint Latin American project identified common problems: difficulty in working with digital images and lack of specific training by medical physicists from the region. Image quality is a main issue not being satisfied in accordance with international recommendations; optimisation processes in which the doses are increased should be very carefully done in order to improve early detection of any cancer signs.

  2. Experience with a proposed teleradiology system for digital mammography

    NASA Astrophysics Data System (ADS)

    Saulnier, Emilie T.; Mitchell, Robert J.; Abdel-Malek, Aiman A.; Dudding, Kathryn E.

    1995-05-01

    Teleradiology offers significant improvement in efficiency and effectiveness over current practices in traditional film/screen-based diagnosis. In the context of digital mammography, the increasing number of women who need to be screened for breast cancer, including those in remote rural regions, make the advantages of teleradiology especially attractive for digital mammography. At the same time, the size and resolution of digital mammograms are among the most challenging to support in a cost effective teleradiology system. This paper describes a teleradiology architecture developed for use with digital mammography by GE Corporate Research and Development in collaboration with Massachusetts General Hospital under National Cancer Institute (NCI/NIH) grant number R01 CA60246-01. Experience with a testbed prototype is described. The telemammography architecture is intended to consist of a main mammography diagnostic site serving several remote screening sites. As patient exams become available, they are forwarded by an image server to the diagnostic site over a WAN communications link. A radiologist at the diagnostic site views a patient exam as it arrives, interprets it, and then relays a report back to the technician at the remote site. A secondary future scenario consists of mobile units which forward images to a remote site, which then forwards them to the main diagnostic site. The testbed architecture is based on the Digital Imaging and Communications in Medicine (DICOM) standard, created by the American College of Radiology (ACR) and National Electrical Manufacturers Association (NEMA). A specification of vendor-independent data formats and data transfer services for digital medical images, DICOM specifies a protocol suite starting at the application layer downward, including the TCP/IP layers. The current DICOM definition does not provide an information element that is specifically tailored to mammography, so we have used the DICOM secondary capture data format

  3. The influence of software filtering in digital mammography image quality

    NASA Astrophysics Data System (ADS)

    Michail, C.; Spyropoulou, V.; Kalyvas, N.; Valais, I.; Dimitropoulos, N.; Fountos, G.; Kandarakis, I.; Panayiotakis, G.

    2009-05-01

    Breast cancer is one of the most frequently diagnosed cancers among women. Several techniques have been developed to help in the early detection of breast cancer such as conventional and digital x-ray mammography, positron and single-photon emission mammography, etc. A key advantage in digital mammography is that images can be manipulated as simple computer image files. Thus non-dedicated commercially available image manipulation software can be employed to process and store the images. The image processing tools of the Photoshop (CS 2) software usually incorporate digital filters which may be used to reduce image noise, enhance contrast and increase spatial resolution. However, improving an image quality parameter may result in degradation of another. The aim of this work was to investigate the influence of three sharpening filters, named hereafter sharpen, sharpen more and sharpen edges on image resolution and noise. Image resolution was assessed by means of the Modulation Transfer Function (MTF).In conclusion it was found that the correct use of commercial non-dedicated software on digital mammograms may improve some aspects of image quality.

  4. A task-based quality control metric for digital mammography

    NASA Astrophysics Data System (ADS)

    Maki Bloomquist, A. K.; Mainprize, J. G.; Mawdsley, G. E.; Yaffe, M. J.

    2014-11-01

    A reader study was conducted to tune the parameters of an observer model used to predict the detectability index (dʹ ) of test objects as a task-based quality control (QC) metric for digital mammography. A simple test phantom was imaged to measure the model parameters, namely, noise power spectrum, modulation transfer function and test-object contrast. These are then used in a non-prewhitening observer model, incorporating an eye-filter and internal noise, to predict dʹ. The model was tuned by measuring dʹ of discs in a four-alternative forced choice reader study. For each disc diameter, dʹ was used to estimate the threshold thicknesses for detectability. Data were obtained for six types of digital mammography systems using varying detector technologies and x-ray spectra. A strong correlation was found between measured and modeled values of dʹ, with Pearson correlation coefficient of 0.96. Repeated measurements from separate images of the test phantom show an average coefficient of variation in dʹ for different systems between 0.07 and 0.10. Standard deviations in the threshold thickness ranged between 0.001 and 0.017 mm. The model is robust and the results are relatively system independent, suggesting that observer model dʹ shows promise as a cross platform QC metric for digital mammography.

  5. Theoretical analysis of high-resolution digital mammography

    NASA Astrophysics Data System (ADS)

    Suryanarayanan, Sankararaman; Karellas, Andrew; Vedantham, Srinivasan; Sechopoulos, Ioannis

    2006-06-01

    The performance of a high-resolution charge coupled device-based full-field digital mammography imager was analysed using a mathematical framework based on an adaptation of cascaded linear systems theory described by other investigators. This work has been conducted in order to understand the impact of various design parameters on the physical performance characteristics of the imager. Specifically, the effect of pixel size, scintillator thickness and packing density, x-ray spectra, air kerma, dark current, charge integration time, and pixel fill-factor on the frequency dependent detective quantum efficiency was studied using a charge-coupled device as a reference platform. The imaging system was modelled as a series of physical processes with gain and spatial spreading. For each stage, the signal and noise power spectra were computed and propagated through the imaging chain as inputs to subsequent stages. Good agreement between experimental and theoretical predictions was obtained for various x-ray spectral conditions that were investigated. The modulation transfer function, MTF(f) and detective quantum efficiency DQE(f) characteristics obtained in this study are encouraging and comparable to other digital mammography systems. The results of this study strongly suggest the feasibility of large area scintillator-based digital mammography imagers with pixel sizes below 100 µm.

  6. Small Field of View Scintimammography Gamma Camera Integrated to a Stereotactic Core Biopsy Digital X-ray System

    SciTech Connect

    Andrew Weisenberger; Fernando Barbosa; T. D. Green; R. Hoefer; Cynthia Keppel; Brian Kross; Stanislaw Majewski; Vladimir Popov; Randolph Wojcik

    2002-10-01

    A small field of view gamma camera has been developed for integration with a commercial stereotactic core biopsy system. The goal is to develop and implement a dual-modality imaging system utilizing scintimammography and digital radiography to evaluate the reliability of scintimammography in predicting the malignancy of suspected breast lesions from conventional X-ray mammography. The scintimammography gamma camera is a custom-built mini gamma camera with an active area of 5.3 cm /spl times/ 5.3 cm and is based on a 2 /spl times/ 2 array of Hamamatsu R7600-C8 position-sensitive photomultiplier tubes. The spatial resolution of the gamma camera at the collimator surface is < 4 mm full-width at half-maximum and a sensitivity of /spl sim/ 4000 Hz/mCi. The system is also capable of acquiring dynamic scintimammographic data to allow for dynamic uptake studies. Sample images of preliminary clinical results are presented to demonstrate the performance of the system.

  7. Digital Mammography with a Mosaic of CCD Arrays

    NASA Technical Reports Server (NTRS)

    Jalink, Antony, Jr. (Inventor); McAdoo, James A. (Inventor)

    1998-01-01

    A digital mammography device uses a mosaic of electronic digital imaging arrays to scan an x-ray image is discussed. The mosaic of arrays is repositioned several times to expose different portions of the image, until the entire image is scanned. The data generated by the arrays during each exposure is stored in a computer. After the final exposure, the computer combines data of the several partial images to produce a composite of the original x-ray image. An aperture plate is used to reduce scatter and the overall exposure of the patient to x-rays.

  8. A comparison of the performance of digital mammography systems.

    PubMed

    Monnin, P; Gutierrez, D; Bulling, S; Guntern, D; Verdun, F R

    2007-03-01

    An objective analysis of image quality parameters was performed for six digital mammography systems. The presampled modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE) for the systems were determined at different doses, for 28 kVp with a Mo/Mo or W/Al target/filter combination and 2 mm of additional aluminium filtration. The flat-panel units have higher MTF and DQE in the mid to high frequency range than standard CR systems. The highest DQE, over the whole dose range, is for the slit-scanning direct photon counting system. Dual-side read CR can overcome the inherent x-ray absorption and signal collection limitations of standard CR mammography, improving the low-frequency DQE by 40%, to the same level as full-field systems, but it does not improve the poor spatial resolution of phosphor.

  9. A comparison of the performance of digital mammography systems

    SciTech Connect

    Monnin, P.; Gutierrez, D.; Bulling, S.; Guntern, D.; Verdun, F. R.

    2007-03-15

    An objective analysis of image quality parameters was performed for six digital mammography systems. The presampled modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE) for the systems were determined at different doses, for 28 kVp with a Mo/Mo or W/Al target/filter combination and 2 mm of additional aluminium filtration. The flat-panel units have higher MTF and DQE in the mid to high frequency range than standard CR systems. The highest DQE, over the whole dose range, is for the slit-scanning direct photon counting system. Dual-side read CR can overcome the inherent x-ray absorption and signal collection limitations of standard CR mammography, improving the low-frequency DQE by 40%, to the same level as full-field systems, but it does not improve the poor spatial resolution of phosphor.

  10. Advantages of gridless full-field digital mammography

    NASA Astrophysics Data System (ADS)

    Nykanen, Kirsi; Siltanen, Samuli

    2003-06-01

    The purpose of the study was to find out whether the image quality in full-field digital mammography can be improved while lowering the patient dose by removing the anti-scatter grid. Moreover, a fast approximate computational algorithm was developed for determining the scattered field in a real mammogram. The method is non-iterative, robust against noise, and works without modification for any scatter-to-primary ratio. Furthermore, it is computationally effective since it is based on fast Fourier transform (FFT). It was found out that the wide dynamic range of digital detectors leads to decrease in patient dose from 10.9% up to 46.6% at breast thickness of 2cm and from 0.8% up to 40.8% at breast thickness of 4cm depending on the efficiency of the removed grid. At constant patient dose the increase in contrast-to-noise ratio is 5.8% - 36.9% and 0.4%-30.0% accordingly at those two breast thickness. The convolution-based X-ray scatter model was considered. The developed scatter removal method was demonstrated with simulated mammograms and applied to clinical full-field digital mammograms acquired with a high-end digital flat panel detector based on amorphous selenium. Errors in reconstructed scattered fields were 0.3% in case of an ideal simulated mammogram and 7.4% in case of a real simulated mammogram (3cm breast). Applications where the scattered field needs to be determined include 3-D mammography and dual-energy breast imaging. In screening mammography gray-scale optimization eliminates the effect of scattering.

  11. Automatic Exposure Control Device for Digital Mammography

    DTIC Science & Technology

    2004-08-01

    developing innovative approaches for controlling DM exposures. These approaches entail using the digital detector and an artificial neural network to...of interest that determine the exposure parameters for the fully exposed image; and (2) to use an artificial neural network to select exposure

  12. Automatic Exposure Control Device for Digital Mammography

    DTIC Science & Technology

    2001-08-01

    developing innovative approaches for controlling DM exposures. These approaches entail using the digital detector and an artificial neural network to...34 regions of interest that determine the exposure parameters for the fully exposed image; and (2) to use an artificial neural network to select exposure

  13. Validation of MTF measurement for digital mammography quality control

    SciTech Connect

    Carton, Ann-Katherine; Vandenbroucke, Dirk; Struye, Luc; Maidment, Andrew D.A.; Kao, Y.-H.; Albert, Michael; Bosmans, Hilde; Marchal, Guy

    2005-06-15

    The modulation transfer function (MTF) describes the spatial resolution properties of imaging systems. In this work, the accuracy of our implementation of the edge method for calculating the presampled MTF was examined. Synthetic edge images with known MTF were used as gold standards for determining the robustness of the edge method. These images simulated realistic data from clinical digital mammography systems, and contained intrinsic system factors that could affect the MTF accuracy, such as noise, scatter, and flat-field nonuniformities. Our algorithm is not influenced by detector dose variations for MTF accuracy up to 1/2 the sampling frequency. We investigated several methods for noise reduction, including truncating the supersampled line spread function (LSF), windowing the LSF, applying a local exponential fit to the LSF, and applying a monotonic constraint to the supersampled edge spread function. Only the monotonic constraint did not introduce a systematic error; the other methods could result in MTF underestimation. Overall, our edge method consistently computed MTFs which were in good agreement with the true MTF. The edge method was then applied to images from a commercial storage-phosphor based digital mammography system. The calculated MTF was affected by the size (sides of 2.5, 5, or 10 cm) and the composition (lead or tungsten) of the edge device. However, the effects on the MTF were observed only with regard to the low frequency drop (LFD). Scatter nonuniformity was dependent on edge size, and could lead to slight underestimation of LFD. Nevertheless, this negative effect could be minimized by using an edge of 5 cm or larger. An edge composed of lead is susceptible to L-fluorescence, which causes overestimation of the LFD. The results of this work are intended to underline the need for clear guidelines if the MTF is to be given a more crucial role in acceptance tests and routine assessment of digital mammography systems: the MTF algorithm and edge

  14. Bone mineral imaging using a digital magnification mammography system

    NASA Astrophysics Data System (ADS)

    Toyofuku, Fukai; Tokumori, Kenji; Higashida, Yoshiharu; Arimura, Hidetaka; Morishita, Junji; Ohki, Masafumi

    2008-03-01

    The measurement of bone mineral content is important for diagnosis of demineralization diseases such as osteoporosis. A reliable method of obtaining bone mineral images using a digital magnification mammography system has been developed. The full-field digital phase contrast mammography (PCM) system, which has a molybdenum target of 0.1mm focal spot size, was used with 1.75 x magnification. We have performed several phantom experiments using aluminum step wedges (0.2 mm - 6.0 mm in thickness) and a bone mineral standard phantom composed of calcium carbonate and polyurethane (CaCO 3 concentration: 26.7 - 939.0 mg/cm 3) within a water or Lucite phantom. X-ray spectra on the exposure field are measured using a CdTe detector for evaluation of heel effect. From the equations of x-ray attenuation and the thickness of the subjects, quantitative images of both components were obtained. The quantitative images of the two components were obtained for different tube voltages of 24 kV to 39 kV. The relative accuracy was less than 2.5% for the entire aluminum thickness of 0.5 to 6.0 mm at 5 cm water thickness. Accuracy of bone mineral thickness was within 3.5% for 5cm water phantom. The magnified quantitative images of a hand phantom significantly increased the visibility of fine structures of bones. The digital magnification mammography system is useful not only for measurement of bone mineral content, but also high-resolution quantitative imaging of trabecular structure.

  15. Predicting contrast detail performance from objective measurements in digital mammography

    NASA Astrophysics Data System (ADS)

    Young, Kenneth C.; Alsager, Abdulaziz; Dance, David R.; Oduko, Jennifer M.; Gundogdu, Ozcan; Spyrou, Nicholas M.

    2009-02-01

    European Guidelines for quality control in digital mammography specify minimum and achievable standards of image quality in terms of threshold contrast, based on readings of images of the CDMAM test object by human observers. However the methodology is time-consuming and has large inter- and intra-observer error. To overcome these problems a software program is available to automatically read CDMAM images. An alternative approach would be to predict threshold contrast from measurements of DQE and MTF using a model of the imaging process. A simple signal-matched noise-integration model has been used to predict the contrast detail response of five different types of commercial digital mammography system (Siemens Inspiration, GE Senographe DS, and three types of Konica Minolta computerised radiography system). Measurements were made of the MTF and DQE of each detector and the noise equivalent apertures calculated. For each system sets of 16 images of the CDMAM test object were acquired at a range of dose levels and contrast-detail plots obtained using human observers and automated reading. The theoretically and experimentally determined threshold contrasts were compared. An encouragingly good level of agreement was found between the experimental data and theoretical predictions.

  16. Primary Non-Hodgkin Lymphoma of the Breast: Ultrasonography, Elastography, Digital Mammography, Contrast-Enhanced Digital Mammography, and Pathology Findings.

    PubMed

    Gkali, Christina An; Chalazonitis, Athanasios N; Feida, Eleni; Giannos, Aris; Sotiropoulou, Maria; Dimitrakakis, Constantine; Loutradis, Dimitrios

    2015-12-01

    Lymphomas constitute approximately 0.15% of malignant mammary neoplasms. Less than 0.5% of all malignant lymphomas involve the breast primarily. Primary non-Hodgkin breast lymphoma is usually right sided. The combined therapy approach, with chemotherapy and radiotherapy, is the most successful treatment. Mastectomy offers no benefit in the treatment of primary non-Hodgkin breast lymphoma. To the author's knowledge, this is the first published case of primary non-Hodgkin breast lymphoma reported with conventional ultrasonography, elastography (both freehand and acoustic radiation force impulse imaging), digital mammography, contrast-enhanced digital mammography, and pathology findings. A 45-year-old woman presented with a lump in the right breast for 2 months. There was no evidence of systemic lymphoma or leukemia when the breast lesion was detected. Imaging findings were negative for lymphoma. Ipsilateral lymph nodes were not palpable. The mass was resected, and histopathology findings were diagnostic of non-Hodgkin lymphoma. Immunohistochemistry was confirmatory of non-Hodgkin lymphoma, diffuse large cell type of B-cell lineage. Although primary and secondary lymphomas of the breast are rare entities, they should be considered in the differential diagnosis of breast malignancies.

  17. Analysis of factors that affect DQE in digital mammography

    NASA Astrophysics Data System (ADS)

    Takamura, Miho; Higaki, Akiko; Kodera, Yoshie

    2005-04-01

    The international standard IEC 62220-1 about DQE measurement of digital X-ray equipment was published in 2003, but mammography systems aren"t applied to this IEC standard because the factor affect measurement is complicated. Especially, the influence to the pre-sampling MTF by edge method when X-ray beam is oblique to detector. The influence of nonuniformity of x-ray intensity by the heel effect on digital Wiener spectrum (WS) doesn"t become clear. A 0.1mm-thick tungsten edge was imaged in the position where X-ray beam was perpendicular to detector plane and in 6cm from chest wall, respectively. And the pre-sampling MTFs were obtained from these edge images. The calculation area of the digital WS within irradiation area was moved in parallel direction to X-ray tube axis, and the digital WS were calculated. The pre-sampling MTFs and the digital WS are calculated by the method based on the IEC proposal. We used MAMMOMAT3000(SIEMENS), MGU-100B(TOSHIBA), M-IV(LORAD) and Senographe DMR+(GE) as X-ray generator. Images were obtained by FCR PROFECT CS (Fujifilm medical). In all equipments and both arrangement directions of the edge test device, pre-sampling MTFs are almost the same, even if the arrangement places of the edge test device varied. In all equipments, when the calculation area was moved about 10cm, the digital WS of the anode side was higher 7.2-17.9% than those of the cathode side. It was found that the dose of anode side was lower about 20% than cathode side from the profile of an exposure image. We think that digital WS modified the nonuniformity of the dose by the heel effect is obtained by multiplying the digital WS by the compensation coefficient obtained by the dose profile, in low spatial frequency.

  18. Near monochromatic X-rays for digital slot-scan mammography: initial findings.

    PubMed

    Diekmann, Felix; Diekmann, S; Richter, K; Bick, U; Fischer, T; Lawaczeck, R; Press, W-R; Schön, K; Weinmann, H-J; Arkadiev, V; Bjeoumikhov, A; Langhoff, N; Rabe, J; Roth, P; Tilgner, J; Wedell, R; Krumrey, M; Linke, U; Ulm, G; Hamm, B

    2004-09-01

    X-ray spectra are composed of a broad bremsspectrum and anode-characteristic emission lines. In mammography typically molybdenum (Mo), rhodium (Rh) or tungsten (W) anodes are used in combination with Mo, Rh or aluminium filters. Only the photons with energies between 17 and 22 keV of the resulting spectrum are suitable for the soft tissue imaging needed for mammography. The aim of this article is to present first results obtained with a monochromator module mounted at the exit of the X-ray tube of a conventional clinical mammography unit. The experimental setup consists of a Siemens Mammomat 300, an X-ray monochromator module and a linear array detector for image acquisition. The technique is similar to the slot-scan technique known from digital mammography. The experimental machine allows to obtain images both with polychromatic and monochromatic X-rays. Initial evaluation of the system was performed by examination of a contrast-detail phantom (CD-MAM-phantom, Nijmegen, The Netherlands). Images done with the new monochromatic technique were compared to images of the phantom done with polychromatic spectra, with film-screen mammography as well as with digital mammography. The new technique with monochromatic slot-scan mammography resulted in correct identification of 93% of the phantom. Digital slot-scan mammography with polychromatic beam resulted in correct identification of 87%, digital full-field mammography in 83% and conventional film-screen mammography in 70% of the phantom. The results suggest that monochromatization has a potential for improving image quality or decreasing dose in X-ray mammography.

  19. Characterization of scatter in digital mammography from physical measurements

    SciTech Connect

    Leon, Stephanie M. Wagner, Louis K.; Brateman, Libby F.

    2014-06-15

    Purpose: That scattered radiation negatively impacts the quality of medical radiographic imaging is well known. In mammography, even slight amounts of scatter reduce the high contrast required for subtle soft-tissue imaging. In current clinical mammography, image contrast is partially improved by use of an antiscatter grid. This form of scatter rejection comes with a sizeable dose penalty related to the concomitant elimination of valuable primary radiation. Digital mammography allows the use of image processing as a method of scatter correction that might avoid effects that negatively impact primary radiation, while potentially providing more contrast improvement than is currently possible with a grid. For this approach to be feasible, a detailed characterization of the scatter is needed. Previous research has modeled scatter as a constant background that serves as a DC bias across the imaging surface. The goal of this study was to provide a more substantive data set for characterizing the spatially-variant features of scatter radiation at the image detector of modern mammography units. Methods: This data set was acquired from a model of the radiation beam as a matrix of very narrow rays or pencil beams. As each pencil beam penetrates tissue, the pencil widens in a predictable manner due to the production of scatter. The resultant spreading of the pencil beam at the detector surface can be characterized by two parameters: mean radial extent (MRE) and scatter fraction (SF). The SF and MRE were calculated from measurements obtained using the beam stop method. Two digital mammography units were utilized, and the SF and MRE were found as functions of target, filter, tube potential, phantom thickness, and presence or absence of a grid. These values were then used to generate general equations allowing the SF and MRE to be calculated for any combination of the above parameters. Results: With a grid, the SF ranged from a minimum of about 0.05 to a maximum of about 0

  20. Physical characteristics of a full-field digital mammography system

    NASA Astrophysics Data System (ADS)

    Suryanarayanan, Sankararaman; Karellas, Andrew; Vedantham, Srinivasan

    2004-11-01

    The physical performance characteristics of a flat-panel clinical full-field digital mammography (FFDM) system were investigated for a variety of mammographic X-ray spectral conditions. The system was investigated using 26 kVp: Mo/Mo, 28 kVp: Mo/Rh, and 30 kVp: Rh/Rh, with polymethyl methacrylate (PMMA) "tissue equivalent material" of thickness 20, 45, and 60 mm for each of three X-ray spectra, resulting in nine different spectral conditions. The experimental results were compared with a theoretical cascaded linear systems-based model that has been developed independently by other investigators. The FFDM imager (Senographe 2000D, GE Medical Systems, Milwaukee, WI) uses an amorphous silicon (aSi:H) photodiode (100 μm pixel) array directly coupled to a cesium iodide (CsI) scintillator. The spatial resolution of the digital mammography system was determined by measuring the presampling modulation transfer function (MTF). The noise power spectra (NPS) of the system were measured under the different mammographic X-ray spectral conditions at an exposure of approximately 10 mR to the detector from which corresponding detective quantum efficiencies (DQE) were determined. The experimental results provide additional information on the performance of the mammographic system for a broader range of experimental conditions than have been reported in the past. The flat-panel imager exhibits favorable physical quality characteristics under the conditions investigated. The experimental results were compared with theoretical estimates under various spectral conditions and demonstrated good agreement.

  1. Evaluation of automatic exposure control options in digital mammography.

    PubMed

    Zhou, Yifang; Scott, Alexander; Allahverdian, Janet; Frankel, Steve

    2014-01-01

    To quantify the trade-offs of dose and image quality among pre-loaded automatic exposure control (AEC) options in digital mammography, two AEC tables from the Hologic Selenia digital mammography system were compared: the default AEC "table 0" and AEC "table 1". Realistically-shaped phantoms consisting of tissue-equivalent material of various thicknesses (4.5 cm-7 cm) were imaged to obtain a figure of merit (FOM), the squared contrast-to-noise ratio per mean glandular dose. To relate the results to pathological findings and to evaluate the overall performance, the measured contrast-to-noise ratios were applied to simulated lesions on the anthropomorphic breast phantom images, producing various lesion configurations which were blindly scored. It was found that the AEC table 1 improves the low contrast FOM by 11% to 20% for the breast thicknesses of 4.5-6 cm. However, for the 7 cm thick breast, the AEC table 1 decreases the low contrast FOM by 17%. For microcalcifications, the AEC table 1 improves the FOM slightly for the breast thicknesses of 4.5--6 cm and decreases it by 18% at a thickness of 7 cm. The lesion simulation showed enhanced contrast due to the AEC table 1 for the breast thicknesses of 5 cm, 6 cm, and 7 cm, but the enhancement gradually reduces as the thickness increases. The lesion reading showed that the microcalcification detection was scored significantly higher from the AEC table 1 for the thicknesses 5 cm, 6 cm, and 7 cm. The corresponding improvement of mass detection scores was also observed but not consistently significant over the thickness range.

  2. Scatter correction in digital mammography based on image deconvolution.

    PubMed

    Ducote, J L; Molloi, S

    2010-03-07

    X-ray scatter is a major cause of nonlinearity in densitometry measurements using digital mammography. Previous scatter correction techniques have primarily used a single scatter point spread function to estimate x-ray scatter. In this study, a new algorithm to correct x-ray scatter based on image convolution was implemented using a spatially variant scatter point spread function which is energy and thickness dependent. The scatter kernel was characterized in terms of its scattering fraction (SF) and scatter radial extent (k) on uniform Lucite phantoms with thickness of 0.8-8.0 cm. The algorithm operates on a pixel-by-pixel basis by grouping pixels of similar thicknesses into a series of mask images that are individually deconvolved using Fourier image analysis with a distinct kernel for each image. The algorithm was evaluated with three Lucite step phantoms and one anthropomorphic breast phantom using a full-field digital mammography system at energies of 24, 28, 31 and 49 kVp. The true primary signal was measured with a multi-hole collimator. The effect on image quality was also evaluated. For all 16 studies, the average mean percentage error in estimating the true primary signal was found to be -2.13% and the average rms percentage error was 2.60%. The image quality was seen to improve at every energy up to 25% at 49 kVp. The results indicate that a technique based on a spatially variant scatter point spread function can accurately estimate x-ray scatter.

  3. Preoperative digital mammography imaging in conservative mastectomy and immediate reconstruction

    PubMed Central

    Angrigiani, Claudio; Hammond, Dennis; Nava, Maurizio; Gonzalez, Eduardo; Rostagno, Roman; Gercovich, Gustavo

    2016-01-01

    Background Digital mammography clearly distinguishes gland tissue density from the overlying non-glandular breast tissue coverage, which corresponds to the existing tissue between the skin and the Cooper’s ligaments surrounding the gland (i.e., dermis and subcutaneous fat). Preoperative digital imaging can determine the thickness of this breast tissue coverage, thus facilitating planning of the most adequate surgical techniques and reconstructive procedures for each case. Methods This study aimed to describe the results of a retrospective study of 352 digital mammograms in 176 patients with different breast volumes who underwent preoperative conservative mastectomies. The breast tissue coverage thickness and its relationship with the breast volume were evaluated. Results The breast tissue coverage thickness ranged from 0.233 to 4.423 cm, with a mean value of 1.952 cm. A comparison of tissue coverage and breast volume revealed a non-direct relationship between these factors. Conclusions Preoperative planning should not depend only on breast volume. Flap evaluations based on preoperative imaging measurements might be helpful when planning a conservative mastectomy. Accordingly, we propose a breast tissue coverage classification (BTCC). PMID:26855903

  4. Breast positioning system for full field digital mammography and digital breast tomosynthesis system

    NASA Astrophysics Data System (ADS)

    Varjonen, Mari; Pamilo, Martti; Hokka, Pirjo; Hokkanen, Riina; Strömmer, Pekka

    2007-03-01

    This paper will present a new breast positioning system for amorphous selenium (a-Se) based full field digital mammography (FFDM) system, which is also a platform of tomosynthesis prototype. Clinical images demonstrate that this method is capable extending the breast away from the chest wall, and maximizing the breast volume. Breast positioning system consists of two transparent moving sheets that apply traction of the breast controlled by motor. Sheets are under and above the compressed breast. Breast positioning sheets pull the breast into the imaging area during the compression. Digital mammography system is based on amorphous selenium flat panel detector (FPD) technology where the overall thickness of the selenium structure is 200 μm, and the pixel size on this detector is 85 μm. Preliminary results will be presented. Clinical study showed increment of the breast volume imaged, and it brought up to 1.0 cm - 2.0 cm more breast tissue. New breast position system also holds a promise of slight decrement of compression force used in the examination. Maximizing the exposured breast tissue is complicated, but important aspect in the breast cancer detection and diagnosis. Increasing the field of view with an additional volume of breast tissue imaged is a key point in digital mammography and digital breast tomosynthesis (DBT).

  5. Digital Mammography: Development of an Advanced Computer-Aided Diagnosis System for Breast Cancer Detection

    DTIC Science & Technology

    2006-05-01

    aided diagnosis of masses with full-field digital mammography,” Acad. Radiol. 9, 4–12 2002. 34D. Gur, J. S. Stalder, L. A. Hardesty , B. Zheng, J. H...Pickett RM , D’Orsi CJ. Stereo- scopic digital mammography: improving detection and diagnosis of breast cancer. Berlin, Germany: International Congress...other is the root-mean-square ( RMS ) distance between the computer and manually identified pectoral boundary. For 118 MLO view mammograms, 99.2% (117

  6. A comprehensive model for quantum noise characterization in digital mammography.

    PubMed

    Monnin, P; Bosmans, H; Verdun, F R; Marshall, N W

    2016-03-07

    A version of cascaded systems analysis was developed specifically with the aim of studying quantum noise propagation in x-ray detectors. Signal and quantum noise propagation was then modelled in four types of x-ray detectors used for digital mammography: four flat panel systems, one computed radiography and one slot-scan silicon wafer based photon counting device. As required inputs to the model, the two dimensional (2D) modulation transfer function (MTF), noise power spectra (NPS) and detective quantum efficiency (DQE) were measured for six mammography systems that utilized these different detectors. A new method to reconstruct anisotropic 2D presampling MTF matrices from 1D radial MTFs measured along different angular directions across the detector is described; an image of a sharp, circular disc was used for this purpose. The effective pixel fill factor for the FP systems was determined from the axial 1D presampling MTFs measured with a square sharp edge along the two orthogonal directions of the pixel lattice. Expectation MTFs were then calculated by averaging the radial MTFs over all possible phases and the 2D EMTF formed with the same reconstruction technique used for the 2D presampling MTF. The quantum NPS was then established by noise decomposition from homogenous images acquired as a function of detector air kerma. This was further decomposed into the correlated and uncorrelated quantum components by fitting the radially averaged quantum NPS with the radially averaged EMTF(2). This whole procedure allowed a detailed analysis of the influence of aliasing, signal and noise decorrelation, x-ray capture efficiency and global secondary gain on NPS and detector DQE. The influence of noise statistics, pixel fill factor and additional electronic and fixed pattern noises on the DQE was also studied. The 2D cascaded model and decompositions performed on the acquired images also enlightened the observed quantum NPS and DQE anisotropy.

  7. Physical characteristics of five clinical systems for digital mammography

    SciTech Connect

    Lazzari, B.; Belli, G.; Gori, C.; Rosselli Del Turco, M.

    2007-07-15

    The purpose of this study was to evaluate and compare the physical characteristics of five clinical systems for digital mammography (GE Senographe 2000D, Lorad Selenia M-IV, Fischer Senoscan, Agfa DM 1000, and IMS Giotto) currently in clinical use. The basic performances of the mammography systems tested were assessed on the basis of response curve, modulation transfer function (MTF), noise power spectrum, noise equivalent quanta (NEQ), and detective quantum efficiency (DQE) in an experimental setting closely resembling the clinical one. As expected, all the full field digital mammography systems show a linear response curve over a dynamic range from 3.5 to 500 {mu}Gy (0.998digital system, the presampling MTF was calculated within a range up to the Nyquist frequency (5 lp/mm for GE Senographe 2000D, 7.1 lp/mm for Lorad Selenia, 9.3 lp/mm for Fischer Senoscan, and 5.88 lp/mm for IMS Giotto detector). The NEQ becomes related to the exposure in a linear behavior starting from about 40.3 {mu}Gy for GE Senographe 2000D, 42.9 {mu}Gy for Lorad Selenia, 41.2 {mu}Gy for Agfa DM1000, <87.6 {mu}Gy for Fischer Senoscan, and 61.3 {mu}Gy for the IMS Giotto. Above those values, the systems can be considered ''quantum noise limited,'' that is the electronic noise is negligible if compared to the quantum noise. The DQE, for several emitted x-ray spectra for each system, i.e., 28 kV p Mo-Mo, Mo-Rh, Rh-Rh, W-Al anode-filter combination, hardened by 40 mm poly(methylmethacrylate) (PMMA) was evaluated. For the five different systems, the DQE at close to zero spatial frequency ranges between 0.25 and 0.63 at 131 {mu}Gy entrance surface air kerma to the detectors. The results of

  8. Physical characteristics of five clinical systems for digital mammography.

    PubMed

    Lazzari, B; Belli, G; Gori, C; Rosselli Del Turco, M

    2007-07-01

    The purpose of this study was to evaluate and compare the physical characteristics of five clinical systems for digital mammography (GE Senographe 2000D, Lorad Selenia M-IV, Fischer Senoscan, Agfa DM 1000, and IMS Giotto) currently in clinical use. The basic performances of the mammography systems tested were assessed on the basis of response curve, modulation transfer function (MTF), noise power spectrum, noise equivalent quanta (NEQ), and detective quantum efficiency (DQE) in an experimental setting closely resembling the clinical one. As expected, all the full field digital mammography systems show a linear response curve over a dynamic range from 3.5 to 500 microGy (0.998digital system, the presampling MTF was calculated within a range up to the Nyquist frequency (5 lp/mm for GE Senographe 2000D, 7.1 lp/mm for Lorad Selenia, 9.3 lp/mm for Fischer Senoscan, and 5.88 lp/mm for IMS Giotto detector). The NEQ becomes related to the exposure in a linear behavior starting from about 40.3 microGy for GE Senographe 2000D, 42.9 microGy for Lorad Selenia, 41.2 microGy for Agfa DM1000, <87.6 microGy for Fischer Senoscan, and 61.3 microGy for the IMS Giotto. Above those values, the systems can be considered "quantum noise limited," that is the electronic noise is negligible if compared to the quantum noise. The DQE, for several emitted x-ray spectra for each system, i.e., 28 kV p Mo-Mo, Mo-Rh, Rh-Rh, W-Al anode-filter combination, hardened by 40 mm poly(methylmethacrylate) (PMMA) was evaluated. For the five different systems, the DQE at close to zero spatial frequency ranges between 0.25 and 0.63 at 131 microGy entrance surface air kerma to the detectors. The results of

  9. Seamless lesion insertion in digital mammography: methodology and reader study

    NASA Astrophysics Data System (ADS)

    Pezeshk, Aria; Petrick, Nicholas; Sahiner, Berkman

    2016-03-01

    Collection of large repositories of clinical images containing verified cancer locations is costly and time consuming due to difficulties associated with both the accumulation of data and establishment of the ground truth. This problem poses a significant challenge to the development of machine learning algorithms that require large amounts of data to properly train and avoid overfitting. In this paper we expand the methods in our previous publications by making several modifications that significantly increase the speed of our insertion algorithms, thereby allowing them to be used for inserting lesions that are much larger in size. These algorithms have been incorporated into an image composition tool that we have made publicly available. This tool allows users to modify or supplement existing datasets by seamlessly inserting a real breast mass or micro-calcification cluster extracted from a source digital mammogram into a different location on another mammogram. We demonstrate examples of the performance of this tool on clinical cases taken from the University of South Florida Digital Database for Screening Mammography (DDSM). Finally, we report the results of a reader study evaluating the realism of inserted lesions compared to clinical lesions. Analysis of the radiologist scores in the study using receiver operating characteristic (ROC) methodology indicates that inserted lesions cannot be reliably distinguished from clinical lesions.

  10. Tree-structured nonlinear filters in digital mammography

    SciTech Connect

    Qian, W.; Clarke, L.P.; Kallergi, M.; Clark, R.A. )

    1994-03-01

    A new class of nonlinear filters with more robust characteristics for noise suppression and detail preservation is proposed for processing digital mammographic images. The new algorithm consists of two major filtering blocks: (a) a multistage tree-structured filter for image enhancement that uses central weighted median filters as basic sub-filtering blocks and (b) a dispersion edge detector. The design of the algorithm also included the use of linear and curved windows to determine whether variable shape windowing could improve detail preservation. First, the noise-suppressing properties of the tree-structured filter were compared to single filters, namely the median and the central weighted median with conventional square and variable shape adaptive windows; simulated images were used for this purpose. Second, the edge detection properties of the tree-structured filter cascaded with the dispersion edge detector were compared to the performance of the dispersion edge detector alone, the Sobel operator, and the single median filter cascaded with the dispersion edge detector. Selected mammographic images with representative biopsy-proven malignancies were processed with all methods and the results were visually evaluated by an expert mammographer. In all applications, the proposed filter suggested better detail preservation, noise suppression, and edge detection than all other approaches and it may prove to be a useful tool for computer-assisted diagnosis in digital mammography.

  11. Tree-structured nonlinear filters in digital mammography.

    PubMed

    Qian, W; Clarke, L P; Kallergi, M; Clark, R A

    1994-01-01

    A new class of nonlinear filters with more robust characteristics for noise suppression and detail preservation is proposed for processing digital mammographic images. The new algorithm consists of two major filtering blocks: (a) a multistage tree-structured filter for image enhancement that uses central weighted median filters as basic sub-filtering blocks and (b) a dispersion edge detector. The design of the algorithm also included the use of linear and curved windows to determine whether variable shape windowing could improve detail preservation. First, the noise-suppressing properties of the tree-structured filter were compared to single filters, namely the median and the central weighted median with conventional square and variable shape adaptive windows; simulated images were used for this purpose. Second, the edge detection properties of the tree-structured filter cascaded with the dispersion edge detector were compared to the performance of the dispersion edge detector alone, the Sobel operator, and the single median filter cascaded with the dispersion edge detector. Selected mammographic images with representative biopsy-proven malignancies were processed with all methods and the results were visually evaluated by an expert mammographer. In all applications, the proposed filter suggested better detail preservation, noise suppression, and edge detection than all other approaches and it may prove to be a useful tool for computer-assisted diagnosis in digital mammography.

  12. Digital information management: a progress report on the National Digital Mammography Archive

    NASA Astrophysics Data System (ADS)

    Beckerman, Barbara G.; Schnall, Mitchell D.

    2002-05-01

    Digital mammography creates very large images, which require new approaches to storage, retrieval, management, and security. The National Digital Mammography Archive (NDMA) project, funded by the National Library of Medicine (NLM), is developing a limited testbed that demonstrates the feasibility of a national breast imaging archive, with access to prior exams; patient information; computer aids for image processing, teaching, and testing tools; and security components to ensure confidentiality of patient information. There will be significant benefits to patients and clinicians in terms of accessible data with which to make a diagnosis and to researchers performing studies on breast cancer. Mammography was chosen for the project, because standards were already available for digital images, report formats, and structures. New standards have been created for communications protocols between devices, front- end portal and archive. NDMA is a distributed computing concept that provides for sharing and access across corporate entities. Privacy, auditing, and patient consent are all integrated into the system. Five sites, Universities of Pennsylvania, Chicago, North Carolina and Toronto, and BWXT Y12, are connected through high-speed networks to demonstrate functionality. We will review progress, including technical challenges, innovative research and development activities, standards and protocols being implemented, and potential benefits to healthcare systems.

  13. Algorithmic scatter correction in dual-energy digital mammography

    SciTech Connect

    Chen, Xi; Mou, Xuanqin; Nishikawa, Robert M.; Lau, Beverly A.; Chan, Suk-tak; Zhang, Lei

    2013-11-15

    Purpose: Small calcifications are often the earliest and the main indicator of breast cancer. Dual-energy digital mammography (DEDM) has been considered as a promising technique to improve the detectability of calcifications since it can be used to suppress the contrast between adipose and glandular tissues of the breast. X-ray scatter leads to erroneous calculations of the DEDM image. Although the pinhole-array interpolation method can estimate scattered radiations, it requires extra exposures to measure the scatter and apply the correction. The purpose of this work is to design an algorithmic method for scatter correction in DEDM without extra exposures.Methods: In this paper, a scatter correction method for DEDM was developed based on the knowledge that scattered radiation has small spatial variation and that the majority of pixels in a mammogram are noncalcification pixels. The scatter fraction was estimated in the DEDM calculation and the measured scatter fraction was used to remove scatter from the image. The scatter correction method was implemented on a commercial full-field digital mammography system with breast tissue equivalent phantom and calcification phantom. The authors also implemented the pinhole-array interpolation scatter correction method on the system. Phantom results for both methods are presented and discussed. The authors compared the background DE calcification signals and the contrast-to-noise ratio (CNR) of calcifications in the three DE calcification images: image without scatter correction, image with scatter correction using pinhole-array interpolation method, and image with scatter correction using the authors' algorithmic method.Results: The authors' results show that the resultant background DE calcification signal can be reduced. The root-mean-square of background DE calcification signal of 1962 μm with scatter-uncorrected data was reduced to 194 μm after scatter correction using the authors' algorithmic method. The range of

  14. Task-based lens design with application to digital mammography.

    PubMed

    Chen, Liying; Barrett, Harrison H

    2005-01-01

    Recent advances in model observers that predict human perceptual performance now make it possible to optimize medical imaging systems for human task performance. We illustrate the procedure by considering the design of a lens for use in an optically coupled digital mammography system. The channelized Hotelling observer is used to model human performance, and the channels chosen are differences of Gaussians. The task performed by the model observer is detection of a lesion at a random but known location in a clustered lumpy background mimicking breast tissue. The entire system is simulated with a Monte Carlo application according to physics principles, and the main system component under study is the imaging lens that couples a fluorescent screen to a CCD detector. The signal-to-noise ratio (SNR) of the channelized Hotelling observer is used to quantify this detectability of the simulated lesion (signal) on the simulated mammographic background. Plots of channelized Hotelling SNR versus signal location for various lens apertures, various working distances, and various focusing places are presented. These plots thus illustrate the trade-off between coupling efficiency and blur in a task-based manner. In this way, the channelized Hotelling SNR is used as a merit function for lens design.

  15. Task-based lens design with application to digital mammography

    PubMed Central

    Chen, Liying; Barrett, Harrison H.

    2006-01-01

    Recent advances in model observers that predict human perceptual performance now make it possible to optimize medical imaging systems for human task performance. We illustrate the procedure by considering the design of a lens for use in an optically coupled digital mammography system. The channelized Hotelling observer is used to model human performance, and the channels chosen are differences of Gaussians. The task performed by the model observer is detection of a lesion at a random but known location in a clustered lumpy background mimicking breast tissue. The entire system is simulated with a Monte Carlo application according to physics principles, and the main system component under study is the imaging lens that couples a fluorescent screen to a CCD detector. The signal-to-noise ratio (SNR) of the channelized Hotelling observer is used to quantify this detectability of the simulated lesion (signal) on the simulated mammographic background. Plots of channelized Hotelling SNR versus signal location for various lens apertures, various working distances, and various focusing places are presented. These plots thus illustrate the trade-off between coupling efficiency and blur in a task-based manner. In this way, the channelized Hotelling SNR is used as a merit function for lens design. PMID:15669625

  16. Task-based lens design with application to digital mammography

    NASA Astrophysics Data System (ADS)

    Chen, Liying; Barrett, Harrison H.

    2005-01-01

    Recent advances in model observers that predict human perceptual performance now make it possible to optimize medical imaging systems for human task performance. We illustrate the procedure by considering the design of a lens for use in an optically coupled digital mammography system. The channelized Hotelling observer is used to model human performance, and the channels chosen are differences of Gaussians. The task performed by the model observer is detection of a lesion at a random but known location in a clustered lumpy background mimicking breast tissue. The entire system is simulated with a Monte Carlo application according to physics principles, and the main system component under study is the imaging lens that couples a fluorescent screen to a CCD detector. The signal-to-noise ratio (SNR) of the channelized Hotelling observer is used to quantify this detectability of the simulated lesion (signal) on the simulated mammographic background. Plots of channelized Hotelling SNR versus signal location for various lens apertures, various working distances, and various focusing places are presented. These plots thus illustrate the trade-off between coupling efficiency and blur in a task-based manner. In this way, the channelized Hotelling SNR is used as a merit function for lens design.

  17. Mammography and Other Screening Tests for Breast Problems

    MedlinePlus

    ... What are the risks of mammography? • What is digital mammography? • What is a clinical breast exam? • How ... mammogram does not increase cancer risk. What is digital mammography? Digital mammography is a type of mammography ...

  18. Comparative Study Of Image Enhancement Algorithms For Digital And Film Mammography

    SciTech Connect

    Delgado-Gonzalez, A.

    2008-08-11

    Here we discuss the application of edge enhancement algorithms on images obtained with a Mammography System which has a Selenium Detector and on the other hand, on images obtained from digitized film mammography. Comparative analysis of such images includes the study of technical aspects of image acquisition, storage, compression and display. A protocol for a local database has been created as a result of this study.

  19. Dose comparison between screen/film and full-field digital mammography.

    PubMed

    Gennaro, Gisella; di Maggio, Cosimo

    2006-11-01

    The study purpose was the comparison between doses delivered by a full-field digital mammography system and a screen/film mammography unit, both using the same type of X-ray tube. Exposure parameters and breast thickness were collected for 300 screen/film (GE Senographe DMR) and 296 digital mammograms (GE Senographe 2000D). The entrance surface air kerma (ESAK) was calculated from anode/filter combination, kV(p) and mAs values and breast thickness, by simulating spectra through a program based on a catalogue of experimental X-ray spectra. The average glandular dose (AGD) was also computed. Results showed an overall reduction of average glandular dose by 27% of digital over screen/film mammography. The dose saving was about 15% for thin and thick breasts, while it was between 30% and 40% for intermediate thicknesses. Full-field digital mammography dose reduction is allowed by wider dynamic range and higher efficiency of digital detector, which can be exposed at higher energy spectra than screen/film mammography, and by the separation between acquisition and displaying processes.

  20. Research in digital mammography and tomosynthesis at the University of Toronto.

    PubMed

    Yaffe, Martin J

    2014-07-01

    There have been major advances in the field of breast cancer imaging since the early 1970s, both in technological improvements and in the use of the methods of medical physics and image analysis to optimize image quality. The introduction of digital mammography in 2000 provided a marked improvement in imaging of dense breasts. In addition, it became possible to produce tomographic and functional images on modified digital mammography systems. Digital imaging also greatly facilitated the extraction of quantitative information from images. My laboratory has been fortunate in being able to participate in some of these exciting developments. I will highlight some of the areas of our research interest which include modeling of the image formation process, development of high-resolution X-ray detectors for digital mammography and investigating new methods for analyzing image quality. I will also describe our more recent work on developing new applications of digital mammography including tomosynthesis, contrast-enhanced mammography, and measurement of breast density. Finally, I will point to a new area for our research--the application of the techniques of medical imaging to making pathology more quantitative to contribute to use of biomarkers for better characterizing breast cancer and directing therapeutic decisions.

  1. Quality control for digital mammography: Part II recommendations from the ACRIN DMIST trial

    SciTech Connect

    Yaffe, Martin J.; Bloomquist, Aili K.; Mawdsley, Gordon E.

    2006-03-15

    The Digital Mammography Imaging Screening Trial (DMIST), conducted under the auspices of the American College of Radiology Imaging Network (ACRIN), is a clinical trial designed to compare the accuracy of digital versus screen-film mammography in a screening population [E. Pisano et al., ACRIN 6652--Digital vs. Screen-Film Mammography, ACRIN (2001)]. Part I of this work described the Quality Control program developed to ensure consistency and optimal operation of the digital equipment. For many of the tests, there were no failures during the 24 months imaging was performed in DMIST. When systems failed, they generally did so suddenly rather than through gradual deterioration of performance. In this part, the utility and effectiveness of those tests are considered. This suggests that after verification of proper operation, routine extensive testing would be of minimal value. A recommended set of tests is presented including additional and improved tests, which we believe meet the intent and spirit of the Mammography Quality Standards Act regulations to ensure that full-field digital mammography systems are functioning correctly, and consistently producing mammograms of excellent image quality.

  2. 21 CFR 892.1715 - Full-field digital mammography system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Full-field digital mammography system. 892.1715 Section 892.1715 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1715 Full-field digital...

  3. 21 CFR 892.1715 - Full-field digital mammography system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Full-field digital mammography system. 892.1715 Section 892.1715 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1715 Full-field digital...

  4. 21 CFR 892.1715 - Full-field digital mammography system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Full-field digital mammography system. 892.1715 Section 892.1715 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1715 Full-field digital...

  5. 21 CFR 892.1715 - Full-field digital mammography system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Full-field digital mammography system. 892.1715 Section 892.1715 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1715 Full-field digital...

  6. FDA & digital mammography: why has FDA required full field digital mammography systems to be regulated as potentially dangerous devices for more than 10 years?

    PubMed

    Nields, Morgan W

    2010-05-01

    Digital mammography is routinely used in the US to screen asymptomatic women for breast cancer and currently over 50% of US screening centers employ the technology. In spite of FDAs knowledge that digital mammography requires less radiation than film mammography and that its equivalence has been proven in a prospective randomized trial, the agency has failed to allow the technology market access via the 510(k) pre market clearance pathway. As a result of the restrictive Pre Market Approval process, only four suppliers have received FDA approval. The resulting lack of a competitive market has kept costs high, restricted technological innovation, and impeded product improvements as a result of PMA requirements. Meanwhile, at least twelve companies are on the market in the EU and the resulting competitive market has lowered costs and provided increased technological choice. A cultural change with new leadership occurred in the early 90's at FDA. The historical culture at the Center for Devices and Radiological Health of collaboration and education gave way to one characterized by a lack of reliance on outside scientific expertise, tolerance of decision making by unqualified reviewers, and an emphasis on enforcement and punishment. Digital mammography fell victim to this cultural change and as a result major innovations like breast CT and computer aided detection technologies are also withheld from the market. The medical device law, currently under review by the Institute of Medicine, should be amended by the Congress so that new technologies can be appropriately classified in accordance with the risk based assessment classification system detailed in Chapter V of the Federal Food, Drug, and Cosmetic Act. A panel of scientific experts chartered by the NIH or IOM should determine the classification appropriate for new technologies that have no historical regulatory framework. This would be binding on FDA. Unless the law is changed we will likely again experience

  7. Mammography

    MedlinePlus

    ... is similar to having a conventional film mammogram. Computer-aided detection (CAD) systems search digitized mammographic images for abnormal areas of ... standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose control methods to ...

  8. Evaluation of clinical image processing algorithms used in digital mammography.

    PubMed

    Zanca, Federica; Jacobs, Jurgen; Van Ongeval, Chantal; Claus, Filip; Celis, Valerie; Geniets, Catherine; Provost, Veerle; Pauwels, Herman; Marchal, Guy; Bosmans, Hilde

    2009-03-01

    Screening is the only proven approach to reduce the mortality of breast cancer, but significant numbers of breast cancers remain undetected even when all quality assurance guidelines are implemented. With the increasing adoption of digital mammography systems, image processing may be a key factor in the imaging chain. Although to our knowledge statistically significant effects of manufacturer-recommended image processings have not been previously demonstrated, the subjective experience of our radiologists, that the apparent image quality can vary considerably between different algorithms, motivated this study. This article addresses the impact of five such algorithms on the detection of clusters of microcalcifications. A database of unprocessed (raw) images of 200 normal digital mammograms, acquired with the Siemens Novation DR, was collected retrospectively. Realistic simulated microcalcification clusters were inserted in half of the unprocessed images. All unprocessed images were subsequently processed with five manufacturer-recommended image processing algorithms (Agfa Musica 1, IMS Raffaello Mammo 1.2, Sectra Mamea AB Sigmoid, Siemens OPVIEW v2, and Siemens OPVIEW v1). Four breast imaging radiologists were asked to locate and score the clusters in each image on a five point rating scale. The free-response data were analyzed by the jackknife free-response receiver operating characteristic (JAFROC) method and, for comparison, also with the receiver operating characteristic (ROC) method. JAFROC analysis revealed highly significant differences between the image processings (F = 8.51, p < 0.0001), suggesting that image processing strongly impacts the detectability of clusters. Siemens OPVIEW2 and Siemens OPVIEW1 yielded the highest and lowest performances, respectively. ROC analysis of the data also revealed significant differences between the processing but at lower significance (F = 3.47, p = 0.0305) than JAFROC. Both statistical analysis methods revealed that the

  9. Threshold contrast visibility of microcalcifications in digital mammography

    NASA Astrophysics Data System (ADS)

    Carton, Ann-Katherine G.; Bosmans, Hilde; Vandenbroucke, Dirk; Van Ongeval, Chantal; Souverijns, Geert; Rogge, Frank; Marchal, Guy

    2004-05-01

    The purpose of this study is to describe a method that allows the calculation of a contrast-detail curve for a particular system configuration using simulated micro calcifications into clinical mammograms. We made use of simulated templates of micro calcifications and adjusted their x-ray transmission coefficients and resolution to the properties of the mammographic system under consideration (4). We expressed the thickness of the simulated micro calcifications in terms of Al equivalence. In a first step we validated that the thickness of very small Al particles with well known size and thickness can be calculated from their x-ray transmission characteristics at a particular X-ray beam energy. Then, micro calcifications with equivalent diameters in the plane of the detector ranging from 300 to 800 μm and thicknesses, expressed in Al equivalent, covering 77 to 800 μm were simulated into the raw data of real clinical images. The procedure was tested on 2 system configurations: the GE Senographe 2000 D and the Se based Agfa Embrace DM1000 system. We adapted the X-ray transmissions and spatial characteristics of the simulated micro calcifications such that the same physical micro calcification could be simulated into images with the specific exposure parameters (Senographe 2000D: 28 kVp-Rh/Rh, Embrace DM1000: 28 kVp-Mo/Rh), compressed breast thickness (42+/-5mm) and detector under consideration. After processing and printing, 3 observers scored the visibility of the micro calcifications. We derived contrast-detail curves. This psychophysical method allows to summarize the performance of a digital mammography detector including processing and visualization.

  10. Impact of the Introduction of Digital Mammography in an Organized Screening Program on the Recall and Detection Rate.

    PubMed

    Campari, Cinzia; Giorgi Rossi, Paolo; Mori, Carlo Alberto; Ravaioli, Sara; Nitrosi, Andrea; Vacondio, Rita; Mancuso, Pamela; Cattani, Antonella; Pattacini, Pierpaolo

    2016-04-01

    In 2012, the Reggio Emilia Breast Cancer Screening Program introduced digital mammography in all its facilities at the same time. The aim of this work is to analyze the impact of digital mammography introduction on the recall rate, detection rate, and positive predictive value. The program actively invites women aged 45-74 years. We included women screened in 2011, all of whom underwent film-screen mammography, and all women screened in 2012, all of whom underwent digital mammography. Double reading was used for all mammograms, with arbitration in the event of disagreement. A total of 42,240 women underwent screen-film mammography and 45,196 underwent digital mammography. The recall rate increased from 3.3 to 4.4% in the first year of digital mammography (relative recall adjusted by age and round 1.46, 95% CI = 1.37-1.56); the positivity rate for each individual reading, before arbitration, rose from 3 to 5.7%. The digital mammography recall rate decreased during 2012: after 12 months, it was similar to the recall rate with screen-film mammography. The detection rate was similar: 5.9/1000 and 5.2/1000 with screen-film and digital mammography, respectively (adjusted relative detection rate 0.95, 95% CI = 0.79-1.13). The relative detection rate for ductal carcinoma in situ remained the same. The introduction of digital mammography to our organized screening program had a negative impact on specificity, thereby increasing the recall rate. The effect was limited to the first 12 months after introduction and was attenuated by the double reading with arbitration. We did not observe any relevant effects on the detection rate.

  11. Breast Adenomyoepithelioma: Ultrasonography, Elastography, Digital Mammography, Contrast-Enhanced Digital Mammography, and Pathology Findings of This Rare Type of Breast Tumor.

    PubMed

    Gkali, Christina An; Chalazonitis, Athanasios N; Feida, Eleni; Dimitrakakis, Constantine; Sotiropoulou, Maria

    2015-09-01

    Breast adenomyoepithelioma is considered as an uncommon breast tumor. It is evaluated as a variant of intraductal papilloma. The treatment of choice is local resection with free margins. It is the first case of breast adenomyoepithelioma reported with conventional ultrasonography, elastography (both free-hand and acoustic radiation force impulse imaging), digital mammography, contrast-enhanced digital mammography, and pathology findings. A 35-year-old white woman presented with a painless lump of the left breast. Treatment was local resection with free margins. There has been no recurrence for 6 months. Although breast adenomyoepithelioma is an uncommon breast tumor, its awareness is imperative because the differential diagnosis from other breast tumors is quite extensive.

  12. Phase contrast digital mammography using molybdenum x-ray: clinical implications in detectability improvement

    NASA Astrophysics Data System (ADS)

    Freedman, Matthew T.; Lo, Shih-Chung B.; Honda, Chika; Makariou, Erini; Sisney, Gale; Pien, Edward; Ohara, Hiromu; Ishisaka, Akira; Shimada, Fumio

    2003-06-01

    We have applied phase imaging on digital mammography to investigate adequate contrast of printed images for digital phase contrast mammography using a practical molybdenum X-ray tube. Phase contrast mammography procedures were performed with defined air gap (e.g., 0.6 m) configuration using customized mammography equipment and a computed radiography (CR) system. Magnified (x2) phase contrast images acquired with 0.0875mm per pixel were mapped onto the laser imager resolution at 0.04375mm per pixel for printing life-size object on wet processing silver halide recording film. For contact mammography of screen-film system, we used MinR2000 system as a baseline method. ACR 156 phantom printed images with contrasts of 2.8, 3.7, 4.9, 5.7 and 6.7 were evaluated by five radiologists. The ACR scores for the life-size image based on the 2 times magnified phase contrast image acquired by the computed radiography were higher than the scores of MinR2000 image, when the contrast of printed images for both methods was 3.7. The ACR scores were lower in the low contrast images (i.e., 2.8) than its higher contrast counterparts (i.e., >= 3.7) for all techniques used. The detectability improvement should be due to higher spatial resolution and lower noise in the phase contrast images.

  13. Tailoring automatic exposure control toward constant detectability in digital mammography

    SciTech Connect

    Salvagnini, Elena; Bosmans, Hilde; Struelens, Lara; Marshall, Nicholas W.

    2015-07-15

    Purpose: The automatic exposure control (AEC) modes of most full field digital mammography (FFDM) systems are set up to hold pixel value (PV) constant as breast thickness changes. This paper proposes an alternative AEC mode, set up to maintain some minimum detectability level, with the ultimate goal of improving object detectability at larger breast thicknesses. Methods: The default “OPDOSE” AEC mode of a Siemens MAMMOMAT Inspiration FFDM system was assessed using poly(methyl methacrylate) (PMMA) of thickness 20, 30, 40, 50, 60, and 70 mm to find the tube voltage and anode/filter combination programmed for each thickness; these beam quality settings were used for the modified AEC mode. Detectability index (d′), in terms of a non-prewhitened model observer with eye filter, was then calculated as a function of tube current-time product (mAs) for each thickness. A modified AEC could then be designed in which detectability never fell below some minimum setting for any thickness in the operating range. In this study, the value was chosen such that the system met the achievable threshold gold thickness (T{sub t}) in the European guidelines for the 0.1 mm diameter disc (i.e., T{sub t} ≤ 1.10 μm gold). The default and modified AEC modes were compared in terms of contrast-detail performance (T{sub t}), calculated detectability (d′), signal-difference-to-noise ratio (SDNR), and mean glandular dose (MGD). The influence of a structured background on object detectability for both AEC modes was examined using a CIRS BR3D phantom. Computer-based CDMAM reading was used for the homogeneous case, while the images with the BR3D background were scored by human observers. Results: The default OPDOSE AEC mode maintained PV constant as PMMA thickness increased, leading to a reduction in SDNR for the homogeneous background 39% and d′ 37% in going from 20 to 70 mm; introduction of the structured BR3D plate changed these figures to 22% (SDNR) and 6% (d′), respectively

  14. A comparison of the performance of modern screen-film and digital mammography systems

    NASA Astrophysics Data System (ADS)

    Monnin, P.; Gutierrez, D.; Bulling, S.; Lepori, D.; Valley, J.-F.; Verdun, F. R.

    2005-06-01

    This work compares the detector performance and image quality of the new Kodak Min-R EV mammography screen-film system with the Fuji CR Profect detector and with other current mammography screen-film systems from Agfa, Fuji and Kodak. Basic image quality parameters (MTF, NPS, NEQ and DQE) were evaluated for a 28 kV Mo/Mo (HVL = 0.646 mm Al) beam using different mAs exposure settings. Compared with other screen-film systems, the new Kodak Min-R EV detector has the highest contrast and a low intrinsic noise level, giving better NEQ and DQE results, especially at high optical density. Thus, the properties of the new mammography film approach those of a fine mammography detector, especially at low frequency range. Screen-film systems provide the best resolution. The presampling MTF of the digital detector has a value of 15% at the Nyquist frequency and, due to the spread size of the laser beam, the use of a smaller pixel size would not permit a significant improvement of the detector resolution. The dual collection reading technology increases significantly the low frequency DQE of the Fuji CR system that can at present compete with the most efficient mammography screen-film systems.

  15. A comparison of the performance of modern screen-film and digital mammography systems.

    PubMed

    Monnin, P; Gutierrez, D; Bulling, S; Lepori, D; Valley, J-F; Verdun, F R

    2005-06-07

    This work compares the detector performance and image quality of the new Kodak Min-R EV mammography screen-film system with the Fuji CR Profect detector and with other current mammography screen-film systems from Agfa, Fuji and Kodak. Basic image quality parameters (MTF, NPS, NEQ and DQE) were evaluated for a 28 kV Mo/Mo (HVL = 0.646 mm Al) beam using different mAs exposure settings. Compared with other screen-film systems, the new Kodak Min-R EV detector has the highest contrast and a low intrinsic noise level, giving better NEQ and DQE results, especially at high optical density. Thus, the properties of the new mammography film approach those of a fine mammography detector, especially at low frequency range. Screen-film systems provide the best resolution. The presampling MTF of the digital detector has a value of 15% at the Nyquist frequency and, due to the spread size of the laser beam, the use of a smaller pixel size would not permit a significant improvement of the detector resolution. The dual collection reading technology increases significantly the low frequency DQE of the Fuji CR system that can at present compete with the most efficient mammography screen-film systems.

  16. AAPM/RSNA physics tutorial for residents: digital mammography: an overview.

    PubMed

    Mahesh, Mahadevappa

    2004-01-01

    Recent advances in digital detector technology have paved the way to full-field digital mammography (FFDM) systems. The performance of these systems has evolved to the point where replacement of screen-film mammography (SFM) systems is becoming realistic. Despite some commonality between the two techniques, there are fundamental differences in how images are recorded, displayed, and stored. These differences necessitate an understanding of the principles of detection and the characteristics of digital images. Several approaches have been taken in the development of FFDM systems: (a) slot scanning with a scintillator and a charge-coupled device (CCD) array, (b) a flat-panel scintillator and an amorphous silicon diode array, (c) a flat-panel amorphous selenium array, (d) a tiled scintillator with fiberoptic tapers and a CCD array, and (e) photostimulable phosphor plates (computed radiography). Although the initial cost of an FFDM system is high compared with that of an SFM system, digital mammography has inherent advantages, such as wide dynamic range, reduction in recall rates, potential for reduction in radiation dose, increased patient throughput, postprocessing capability, and digital acquisition. These advantages and the rapidly occurring technologic developments will help establish FFDM as a mainstay of breast evaluation.

  17. Digital versus screen-film mammography: impact of mammographic density and hormone therapy on breast cancer detection.

    PubMed

    Chiarelli, Anna M; Prummel, Maegan V; Muradali, Derek; Shumak, Rene S; Majpruz, Vicky; Brown, Patrick; Jiang, Hedy; Done, Susan J; Yaffe, Martin J

    2015-11-01

    Most studies that have examined the effects of mammographic density and hormone therapy use on breast cancer detection have included screen-film mammography. This study further examines this association in post-menopausal women screened by digital mammography. Approved by the University of Toronto Research Ethics Board, this study identified 688,418 women of age 50-74 years screened with digital or screen-film mammography from 2008 to 2009 within the Ontario Breast Screening Program. Of 2993 eligible women with invasive breast cancer, 2450 were contacted and 1421 participated (847 screen-film mammography, 574 digital direct radiography). Mammographic density was measured by study radiologists using the standard BI-RADS classification system and by a computer-assisted method. Information on hormone therapy use was collected by a telephone-administered questionnaire. Logistic regression and two-tailed tests for significance evaluated associations between factors and detection method by mammography type. Women with >75 % radiologist-measured mammographic density compared to those with <25 % were more likely to be diagnosed with an interval than screen-detected cancer, with the difference being greater for those screened with screen-film (OR = 6.40, 95 % CI 2.30-17.85) than digital mammography (OR = 2.41, 95 % CI 0.67-8.58) and aged 50-64 years screened with screen-film mammography (OR = 10.86, 95 % CI 2.96-39.57). Recent former hormone therapy users were also at an increased risk of having an interval cancer with the association being significant for women screened with digital mammography (OR = 2.08, 95 % CI 1.17-3.71). Breast screening using digital mammography lowers the risk of having an interval cancer for post-menopausal women aged 50-64 with greater mammographic density.

  18. Comparison of full-field digital mammography to screen-film mammography with respect to contrast and spatial resolution in tissue equivalent breast phantoms.

    PubMed

    Kuzmiak, Cherie M; Pisano, Etta D; Cole, Elodia B; Zeng, Donglin; Burns, Charles B; Roberto, Craig; Pavic, Dag; Lee, Yeonhee; Seo, Bo Kyoung; Koomen, Marcia; Washburn, David

    2005-10-01

    To determine if the improved contrast resolution of full-field digital mammography (FFDM) with reduced spatial resolution allows for superior or equal phantom object detection compared with screen-film mammography (SFM). Tissue equivalent breast phantoms simulating an adipose to glandular ratio of 50/50,30/70, and 20/80 were imaged according to each manufacturers' recommendation with four full-field digital mammography units (Fuji, Sectra, Fischer, and General Electric) and a screen-film mammography unit (MammoMatII 2000, Siemens, Munich, Germany). A total of 20 images were obtained in both hard- and soft-copy formats. For the purpose of soft-copy display, the screen-film hard-copy images were digitized with a 50 microm micron scanner. Six radiologists, experts in breast imaging, and three physicists, experts in scoring mammography phantoms, participated in a reader study where each reader scored each phantom for visibility of line-pairs and for 24 objects (fibers, clusters of specks, and masses). The data were recorded, entered into a database, and analyzed by a mixed-effect model. The limiting spatial resolution in line-pairs per millimeter visible with the digital units was less, regardless of display modality used, than that provided by the screen-film unit. The difference was statistically significant for the General Electric (p < 0.01) and Fuji digital mammography units (p = 0.03). With respect to the number of visible objects, a statistically significant higher number could be detected with the screen-film unit as compared to the Fischer (p < 0.01) and Sectra (p < 0.01) digital mammography units, but there was no significant difference between the other digital units and screen film. Overall, there was significantly better performance on the 50/50 phantom than with the 30/70 and 20/80 phantoms (p = 0.01, p < 0.01) for object visibility. For the digital mammography units, soft-copy display performed better than hard-copy display for the Fischer and Sectra

  19. Contrast-Medium-Enhanced Digital Mammography: Contrast vs. Iodine Concentration Phantom Calibration

    SciTech Connect

    Rosado-Mendez, I.; Brandan, M. E.; Villasenor, Y.; Benitez-Bribiesca, L.

    2008-08-11

    This work deals with the application of the contrast-medium-enhanced digital subtraction mammography technique in order to calibrate the contrast level in subtracted phantom images as function of iodine concentration to perform dynamic studies of the contrast-medium uptake in the breast. Previously optimized dual-energy temporal subtraction modalities were used (a) to determine radiological parameters for a dynamic clinical study composed of 1 mask+3 post-contrast images limiting the total mean glandular dose to 2.5 mGy, and (b) to perform a contrast vs iodine concentration calibration using a custom-made phantom. Calculated exposure values were applied using a commercial full-field digital mammography unit. Contrast in subtracted phantom images (one mask and one post-CM) is linear as function of iodine concentration, although the sensitivity (contrast per iodine concentration) decreases beyond 8 mg/mL. This calibration seems to apply only to thin and normal thickness breasts.

  20. Lag and ghosting in a clinical flat-panel selenium digital mammography system

    SciTech Connect

    Bloomquist, Aili K.; Yaffe, Martin J.; Mawdsley, Gordon E.; Hunter, David M.; Beideck, Daniel J.

    2006-08-15

    We present measurements of lag and ghosting in a FDA-approved digital mammography system that uses a dielectric/selenium based detector structure. Lag is the carryover of signal from a previous image, whereas ghosting is the reduction of sensitivity caused by previous exposure history of the detector. Data from six selenium units were acquired. For the type of selenium detector tested, and under typical clinical usage conditions, the lag was as high as 0.15% of source signal and the ghosting could be as high as 15%. The amount of lag and ghosting varied from unit to unit. Results were compared with data acquired on a phosphor-based full-field digital mammography system. Modifications in the technology of the selenium detectors appear to have resulted in a marked decrease in both lag and ghosting effects in more recent systems.

  1. Mean glandular dose in six digital mammography services in Santiago, Chile: preliminary reference levels.

    PubMed

    Leyton, Fernando; Nogueira, Maria Do Socorro; Dantas, Marcelino; Duran, Maria Paz; Ubeda, Carlos

    2015-07-01

    The purpose of this paper was to estimate mean glandular dose levels (DG) in six digital mammography systems in Santiago, Chile, and to propose preliminary reference levels to execute mammography in Chile. The study was carried out assessing two direct digital systems and four computer-based radiography (CR) systems. Estimates of DG were calculated for different thicknesses of polymethyl methacrylate according to the quality control protocol in digital mammography of the Spanish Society of Medical Physics and NHSBSP Equipment Report 0604 Version 3. DG values ranged between 0.64 and 7.26 mGy for a range of 20- to 70-mm thickness, respectively. Thirty-six per cent of DG was higher than the acceptable dose level and 100 % of DG was higher than the desirable level. It is therefore necessary to optimise doses. The initial proposal to establish dose reference levels for DG would range between 0.90 and 6.40 mGy for a thickness range of 20 to 70 mm.

  2. Automated analysis of phantom images for the evaluation of long-term reproducibility in digital mammography

    NASA Astrophysics Data System (ADS)

    Gennaro, G.; Ferro, F.; Contento, G.; Fornasin, F.; di Maggio, C.

    2007-03-01

    The performance of an automatic software package was evaluated with phantom images acquired by a full-field digital mammography unit. After the validation, the software was used, together with a Leeds TORMAS test object, to model the image acquisition process. Process modelling results were used to evaluate the sensitivity of the method in detecting changes of exposure parameters from routine image quality measurements in digital mammography, which is the ultimate purpose of long-term reproducibility tests. Image quality indices measured by the software included the mean pixel value and standard deviation of circular details and surrounding background, contrast-to-noise ratio and relative contrast; detail counts were also collected. The validation procedure demonstrated that the software localizes the phantom details correctly and the difference between automatic and manual measurements was within few grey levels. Quantitative analysis showed sufficient sensitivity to relate fluctuations in exposure parameters (kVp or mAs) to variations in image quality indices. In comparison, detail counts were found less sensitive in detecting image quality changes, even when limitations due to observer subjectivity were overcome by automatic analysis. In conclusion, long-term reproducibility tests provided by the Leeds TORMAS phantom with quantitative analysis of multiple IQ indices have been demonstrated to be effective in predicting causes of deviation from standard operating conditions and can be used to monitor stability in full-field digital mammography.

  3. Contrast-enhanced digital mammography (CEDM): phantom experiment and first clinical results

    NASA Astrophysics Data System (ADS)

    Marx, Christiane; Facius, Mirijam; Muller, Serge L.; Benali, Karim; Malich, Ansgar; Kaiser, Werner

    2002-05-01

    The introduction of the Full Field Digital Mammography (FFDM) opens the way to a large range of future advanced applications. Among them, Contrast Enhanced Digital Mammography (CEDM) could be a fast and less expensive alternative to Magnetic Resonance Imaging (MRI) for breast lesion characterization. In this work, we have investigated, first on phantom then on patients, the capability of a modified FFDM system to show the contrast enhancement of lesions after intra-venous injection of iodine. The uptake has been estimated from the difference between pre- and post-contrast images. Phantom results showed that 1) detectability thresholds of the contrast media were compatible with clinical conditions; 2) breast radiological thickness has a low impact on uptake detectability; 3) spatial and temporal analysis showed delayed margin contrast uptake of the simulated lesion and slow increase of contrast in the background. Preliminary results on patients have confirmed the phantom results and have shown a contrast uptake in all malignant lesions despite the observed patient motion artifacts, and some moderate signal variability. This study demonstrated the feasibility of the Contrast Enhanced Digital Mammography technique. Further investigations and clinical validations will have to be completed before it can be widely used in a daily routine practice.

  4. Implementation of Synthesized Two-dimensional Mammography in a Population-based Digital Breast Tomosynthesis Screening Program.

    PubMed

    Zuckerman, Samantha P; Conant, Emily F; Keller, Brad M; Maidment, Andrew D A; Barufaldi, Bruno; Weinstein, Susan P; Synnestvedt, Marie; McDonald, Elizabeth S

    2016-12-01

    Purpose To evaluate the early implementation of synthesized two-dimensional (s2D) mammography in a population screened entirely with s2D and digital breast tomosynthesis (DBT) (referred to as s2D/DBT) and compare recall rates and cancer detection rates to historic outcomes of digital mammography combined with DBT (referred to as digital mammography/DBT) screening. Materials and Methods This was an institutional review board-approved and HIPAA-compliant retrospective interpretation of prospectively acquired data with waiver of informed consent. Compared were recall rates, biopsy rates, cancer detection rates, and radiation dose for 15 571 women screened with digital mammography/DBT from October 1, 2011, to February 28, 2013, and 5366 women screened with s2D/DBT from January 7, 2015, to June 30, 2015. Two-sample z tests of equal proportions were used to determine statistical significance. Results Recall rate for s2D/DBT versus digital mammography/DBT was 7.1% versus 8.8%, respectively (P < .001). Biopsy rate for s2D/DBT versus digital mammography/DBT decreased (1.3% vs 2.0%, respectively; P = .001). There was no significant difference in cancer detection rate for s2D/DBT versus digital mammography/DBT (5.03 of 1000 vs 5.45 of 1000, respectively; P = .72). The average glandular dose was 39% lower in s2D/DBT versus digital mammography/DBT (4.88 mGy vs 7.97 mGy, respectively; P < .001). Conclusion Screening with s2D/DBT in a large urban practice resulted in similar outcomes compared with digital mammography/DBT imaging. Screening with s2D/DBT allowed for the benefits of DBT with a decrease in radiation dose compared with digital mammography/DBT. (©) RSNA, 2016 An earlier incorrect version of this article appeared online. This article was corrected on August 11, 2016.

  5. Dual-energy contrast-enhanced digital mammography: initial clinical results of a multireader, multicase study

    PubMed Central

    2012-01-01

    Introduction The purpose of this study was to compare the diagnostic accuracy of dual-energy contrast-enhanced digital mammography (CEDM) as an adjunct to mammography (MX) ± ultrasonography (US) with the diagnostic accuracy of MX ± US alone. Methods One hundred ten consenting women with 148 breast lesions (84 malignant, 64 benign) underwent two-view dual-energy CEDM in addition to MX and US using a specially modified digital mammography system (Senographe DS, GE Healthcare). Reference standard was histology for 138 lesions and follow-up for 12 lesions. Six radiologists from 4 institutions interpreted the images using high-resolution softcopy workstations. Confidence of presence (5-point scale), probability of cancer (7-point scale), and BI-RADS scores were evaluated for each finding. Sensitivity, specificity and ROC curve areas were estimated for each reader and overall. Visibility of findings on MX ± CEDM and MX ± US was evaluated with a Likert scale. Results The average per-lesion sensitivity across all readers was significantly higher for MX ± US ± CEDM than for MX ± US (0.78 vs. 0.71 using BIRADS, p = 0.006). All readers improved their clinical performance and the average area under the ROC curve was significantly superior for MX ± US ± CEDM than for MX ± US ((0.87 vs 0.83, p = 0.045). Finding visibility was similar or better on MX ± CEDM than MX ± US in 80% of cases. Conclusions Dual-energy contrast-enhanced digital mammography as an adjunct to MX ± US improves diagnostic accuracy compared to MX ± US alone. Addition of iodinated contrast agent to MX facilitates the visualization of breast lesions. PMID:22697607

  6. Are phantoms useful for predicting the potential of dose reduction in full-field digital mammography?

    NASA Astrophysics Data System (ADS)

    Gennaro, Gisella; Katz, Luc; Souchay, Henri; Alberelli, Claudio; di Maggio, Cosimo

    2005-04-01

    A phantom study was performed in full-field digital mammography to investigate the opportunity and the magnitude of a possible dose reduction that would leave the image quality above the accepted thresholds associated with some classical phantoms. This preliminary work is intended to lay the groundwork for a future clinical study on the impact of dose reduction on clinical results. Three different mammography phantoms (ACR RMI 156, CIRS 11A and CDMAM 3.4) were imaged by a full-field digital mammography unit (GE Senographe 2000D) at different dose levels. Images were rated by three observers with softcopy reading and scoring methods specific to each phantom. Different types of data analysis were applied to the ACR (American College of Radiology) and the other two phantoms, respectively. With reference to the minimum acceptance score in screen/film accreditation programmes, the ACR phantom showed that about 45% dose reduction could be applied, while keeping the phantom scores above that threshold. A relative comparison was done for CIRS and CDMAM, for which no threshold is defined. CIRS scoring remained close to the reference level down to 40% dose reduction, the inter- and intra-observer variability being the main source of uncertainty. Contrast-detail curves provided by CDMAM overlapped down to 50% dose reduction, at least for object contrast values ranging between 30% and 3%. This multi-phantom study shows the potential of further reducing the dose in full-field digital mammography beyond the current values. A common dose reduction factor around 50% seems acceptable for all phantoms. However, caution is required before extrapolating the results for clinical use, given the limitations of these widely used phantoms, mainly related to their limited dynamic range and uniform background.

  7. Estimation of percentage breast tissue density: comparison between digital mammography (2D full field digital mammography) and digital breast tomosynthesis according to different BI-RADS categories

    PubMed Central

    Cavagnetto, F; Calabrese, M; Houssami, N

    2013-01-01

    Objective: To compare breast density estimated from two-dimensional full-field digital mammography (2D FFDM) and from digital breast tomosynthesis (DBT) according to different Breast Imaging–Reporting and Data System (BI-RADS) categories, using automated software. Methods: Institutional review board approval and written informed patient consent were obtained. DBT and 2D FFDM were performed in the same patients to allow within-patient comparison. A total of 160 consecutive patients (mean age: 50±14 years; mean body mass index: 22±3) were included to create paired data sets of 40 patients for each BI-RADS category. Automatic software (MedDensity©, developed by Giulio Tagliafico) was used to compare the percentage breast density between DBT and 2D FFDM. The estimated breast percentage density obtained using DBT and 2D FFDM was examined for correlation with the radiologists' visual BI-RADS density classification. Results: The 2D FFDM differed from DBT by 16.0% in BI-RADS Category 1, by 11.9% in Category 2, by 3.5% in Category 3 and by 18.1% in Category 4. These differences were highly significant (p<0.0001). There was a good correlation between the BI-RADS categories and the density evaluated using 2D FFDM and DBT (r=0.56, p<0.01 and r=0.48, p<0.01, respectively). Conclusion: Using DBT, breast density values were lower than those obtained using 2D FFDM, with a non-linear relationship across the BI-RADS categories. These data are relevant for clinical practice and research studies using density in determining the risk. Advances in knowledge: On DBT, breast density values were lower than with 2D FFDM, with a non-linear relationship across the classical BI-RADS categories. PMID:24029631

  8. Comparative performance of modern digital mammography systems in a large breast screening program

    SciTech Connect

    Yaffe, Martin J. Bloomquist, Aili K.; Hunter, David M.; Mawdsley, Gordon E.; Chiarelli, Anna M.; Muradali, Derek; Mainprize, James G.

    2013-12-15

    Purpose: To compare physical measures pertaining to image quality among digital mammography systems utilized in a large breast screening program. To examine qualitatively differences in these measures and differences in clinical cancer detection rates between CR and DR among sites within that program. Methods: As part of the routine quality assurance program for screening, field measurements are made of several variables considered to correlate with the diagnostic quality of medical images including: modulation transfer function, noise equivalent quanta, d′ (an index of lesion detectability) and air kerma to allow estimation of mean glandular dose. In addition, images of the mammography accreditation phantom are evaluated. Results: It was found that overall there were marked differences between the performance measures of DR and CR mammography systems. In particular, the modulation transfer functions obtained with the DR systems were found to be higher, even for larger detector element sizes. Similarly, the noise equivalent quanta, d′, and the phantom scores were higher, while the failure rates associated with low signal-to-noise ratio and high dose were lower with DR. These results were consistent with previous findings in the authors’ program that the breast cancer detection rates at sites employing CR technology were, on average, 30.6% lower than those that used DR mammography. Conclusions: While the clinical study was not large enough to allow a statistically powered system-by-system assessment of cancer detection accuracy, the physical measures expressing spatial resolution, and signal-to-noise ratio are consistent with the published finding that sites employing CR systems had lower cancer detection rates than those using DR systems for screening mammography.

  9. Radiation dose differences between digital mammography and digital breast tomosynthesis are dependent on breast thickness

    NASA Astrophysics Data System (ADS)

    Alakhras, Maram M.; Mello-Thoms, Claudia; Bourne, Roger; Rickard, Mary; Diffey, Jennifer; Brennan, Patrick C.

    2016-03-01

    Purpose To evaluate the radiation dose derived from digital mammography (DM) and digital breast tomosynthesis (DBT) at different tube current-exposure time product (mAs) and at 6 phantom thicknesses from 10 to 60 mm. Materials and Methods A total of 240 DM and DBT cranio-caudal (CC) phantom images were acquired at each thickness and at four exposure levels (the baseline mAs, 50%, 25% and 12.5% the baseline mAs). The incident Air Kerma (K) at the surface of the phantoms was measured using a solid state dosimeter. Mean Glandular Doses (MGD) were calculated for both modalities (DM and DBT). Results DBT dose was greater than that of DM for all mAs at each phantom thickness. For a breast thickness of 50 mm (close to average sized breast), the dose for DBT (2.32 mGy) was 13% higher than that for DM (2.05 mGy). The results also show that the difference in MGD between DM and DBT was less for the thicker compared with the thinner phantom, this difference being approximately a factor of 2.58 at 10 mm compared with a factor of 1.08 at 60 mm. While the MGD increased with increasing phantom thickness for both modalities, the dose increase with DBT was less than for DM, with the difference between 10 and 60 mm being a factor of 7 for DM and 3 for DBT. Conclusion The radiation dose from DBT was higher than that of DM and the difference in dose between DM and DBT decreases as phantom thickness increases.

  10. A comparison of image interpretation times in full field digital mammography and digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Astley, Susan; Connor, Sophie; Lim, Yit; Tate, Catriona; Entwistle, Helen; Morris, Julie; Whiteside, Sigrid; Sergeant, Jamie; Wilson, Mary; Beetles, Ursula; Boggis, Caroline; Gilbert, Fiona

    2013-03-01

    Digital Breast Tomosynthesis (DBT) provides three-dimensional images of the breast that enable radiologists to discern whether densities are due to overlapping structures or lesions. To aid assessment of the cost-effectiveness of DBT for screening, we have compared the time taken to interpret DBT images and the corresponding two-dimensional Full Field Digital Mammography (FFDM) images. Four Consultant Radiologists experienced in reading FFDM images (4 years 8 months to 8 years) with training in DBT interpretation but more limited experience (137-407 cases in the past 6 months) were timed reading between 24 and 32 two view FFDM and DBT cases. The images were of women recalled from screening for further assessment and women under surveillance because of a family history of breast cancer. FFDM images were read before DBT, according to local practice. The median time for readers to interpret FFDM images was 17.0 seconds, with an interquartile range of 12.3-23.6 seconds. For DBT, the median time was 66.0 seconds, and the interquartile range was 51.1-80.5 seconds. The difference was statistically significant (p<0.001). Reading times were significantly longer in family history clinics (p<0.01). Although it took approximately four times as long to interpret DBT than FFDM images, the cases were more complex than would be expected for routine screening, and with higher mammographic density. The readers were relatively inexperienced in DBT interpretation and may increase their speed over time. The difference in times between clinics may be due to increased throughput at assessment, or decreased density.

  11. Comparison of computer-aided detection of clustered microcalcifications in digital mammography and digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Samala, Ravi K.; Chan, Heang-Ping; Lu, Yao; Hadjiiski, Lubomir; Wei, Jun; Helvie, Mark

    2015-03-01

    Digital breast tomosynthesis (DBT) has the potential to replace digital mammography (DM) for breast cancer screening. An effective computer-aided detection (CAD) system for microcalcification clusters (MCs) on DBT will facilitate the transition. In this study, we collected a data set with corresponding DBT and DM for the same breasts. DBT was acquired with IRB approval and informed consent using a GE GEN2 DBT prototype system. The DM acquired with a GE Essential system for the patient's clinical care was collected retrospectively from patient files. DM-based CAD (CADDM) and DBT-based CAD (CADDBT) were previously developed by our group. The major differences between the CAD systems include: (a) CADDBT uses two parallel processes whereas CADDM uses a single process for enhancing MCs and removing the structured background, (b) CADDBT has additional processing steps to reduce the false positives (FPs), including ranking of candidates of cluster seeds and cluster members and the use of adaptive CNR and size thresholds at clustering and FP reduction, (c) CADDM uses convolution neural network (CNN) and linear discriminant analysis (LDA) to differentiate true microcalcifications from FPs based on their morphological and CNN features. The performance difference is assessed by FROC analysis using test set (100 views with MCs and 74 views without MCs) independent of their respective training sets. At sensitivities of 70% and 80%, CADDBT achieved FP rates of 0.78 and 1.57 per view compared to 0.66 and 2.10 per image for the CADDM. JAFROC showed no significant difference between MC detection on DM and DBT by the two CAD systems.

  12. Dosimetry and image quality in digital mammography facilities in the State of Minas Gerais, Brazil

    NASA Astrophysics Data System (ADS)

    da Silva, Sabrina Donato; Joana, Geórgia Santos; Oliveira, Bruno Beraldo; de Oliveira, Marcio Alves; Leyton, Fernando; Nogueira, Maria do Socorro

    2015-11-01

    According to the National Register of Health Care Facilities (CNES), there are approximately 477 mammography systems operating in the state of Minas Gerais, Brazil, of which an estimated 200 are digital apparatus using mainly computerized radiography (CR) or direct radiography (DR) systems. Mammography is irreplaceable in the diagnosis and early detection of breast cancer, the leading cause of cancer death among women worldwide. A high standard of image quality alongside smaller doses and optimization of procedures are essential if early detection is to occur. This study aimed to determine dosimetry and image quality in 68 mammography services in Minas Gerais using CR or DR systems. The data of this study were collected between the years of 2011 and 2013. The contrast-to-noise ratio proved to be a critical point in the image production chain in digital systems, since 90% of services were not compliant in this regard, mainly for larger PMMA thicknesses (60 and 70 mm). Regarding the image noise, only 31% of these were compliant. The average glandular dose found is of concern, since more than half of the services presented doses above acceptable limits. Therefore, despite the potential benefits of using CR and DR systems, the employment of this technology has to be revised and optimized to achieve better quality image and reduce radiation dose as much as possible.

  13. Exploratory survey of image quality on CR digital mammography imaging systems in Mexico.

    PubMed

    Gaona, E; Rivera, T; Arreola, M; Franco, J; Molina, N; Alvarez, B; Azorín, C G; Casian, G

    2014-01-01

    The purpose of this study was to assess the current status of image quality and dose in computed radiographic digital mammography (CRDM) systems. Studies included CRDM systems of various models and manufacturers which dose and image quality comparisons were performed. Due to the recent rise in the use of digital radiographic systems in Mexico, CRDM systems are rapidly replacing conventional film-screen systems without any regard to quality control or image quality standards. Study was conducted in 65 mammography facilities which use CRDM systems in the Mexico City and surrounding States. The systems were tested as used clinically. This means that the dose and beam qualities were selected using the automatic beam selection and photo-timed features. All systems surveyed generate laser film hardcopies for the radiologist to read on a scope or mammographic high luminance light box. It was found that 51 of CRDM systems presented a variety of image artefacts and non-uniformities arising from inadequate acquisition and processing, as well as from the laser printer itself. Undisciplined alteration of image processing settings by the technologist was found to be a serious prevalent problem in 42 facilities. Only four of them showed an image QC program which is periodically monitored by a medical physicist. The Average Glandular Dose (AGD) in the surveyed systems was estimated to have a mean value of 2.4 mGy. To improve image quality in mammography and make more efficient screening mammographic in early detection of breast cancer is required new legislation.

  14. Assessment of mass detection performance in contrast enhanced digital mammography

    NASA Astrophysics Data System (ADS)

    Carton, Ann-Katherine; de Carvalho, Pablo M.; Li, Zhijin; Dromain, Clarisse; Muller, Serge

    2015-03-01

    We address the detectability of contrast-agent enhancing masses for contrast-agent enhanced spectral mammography (CESM), a dual-energy technique providing functional projection images of breast tissue perfusion and vascularity using simulated CESM images. First, the realism of simulated CESM images from anthropomorphic breast software phantoms generated with a software X-ray imaging platform was validated. Breast texture was characterized by power-law coefficients calculated in data sets of real clinical and simulated images. We also performed a 2-alternative forced choice (2-AFC) psychophysical experiment whereby simulated and real images were presented side-by-side to an experienced radiologist to test if real images could be distinguished from the simulated images. It was found that texture in our simulated CESM images has a fairly realistic appearance. Next, the relative performance of human readers and previously developed mathematical observers was assessed for the detection of iodine-enhancing mass lesions containing different contrast agent concentrations. A four alternative-forced-choice (4 AFC) task was designed; the task for the model and human observer was to detect which one of the four simulated DE recombined images contained an iodineenhancing mass. Our results showed that the NPW and NPWE models largely outperform human performance. After introduction of an internal noise component, both observers approached human performance. The CHO observer performs slightly worse than the average human observer. There is still work to be done in improving model observers as predictors of human-observer performance. Larger trials could also improve our test statistics. We hope that in the future, this framework of software breast phantoms, virtual image acquisition and processing, and mathematical observers can be beneficial to optimize CESM imaging techniques.

  15. Optimal photon energy comparison between digital breast tomosynthesis and mammography: a case study.

    PubMed

    Di Maria, S; Baptista, M; Felix, M; Oliveira, N; Matela, N; Janeiro, L; Vaz, P; Orvalho, L; Silva, A

    2014-06-01

    A comparison, in terms of the optimal energy that maximizes the image quality between digital breast tomosynthesis (DBT) and digital mammography (DM) was performed in a MAMMOMAT Inspiration system (Siemens) based on amorphous selenium flat panel detector. In this paper we measured the image quality by the signal difference-to-noise ratio (SDNR), and the patient risk by the mean glandular dose (MGD). Using these quantities we compared the optimal voltage that maximizes the image quality both in breast tomosynthesis and standard mammography acquisition mode. The comparison for the two acquisition modes was performed for a W/Rh anode filter combinations by using a 4.5 cm tissue equivalent mammography phantom. Moreover, in order to check if the used equipment was quantum noise limited, the relation of the relative noise with respect to the detector dose was evaluated. Results showed that in the tomosynthesis acquisition mode the optimal voltage is 28 kV, whereas in standard mammography the optimal voltage is 30 kV. The automatic exposure control (AEC) of the system selects 28 kV as optimal voltage both for DBT and DM. Monte Carlo simulations showed a qualitative agreement with the AEC selection system, since an optimal monochromatic energy of 20 keV was found both for DBT and DM. Moreover, the check about the noise showed that the system is not completely quantum noise limited, and this issue could explain the experimental slight difference in terms of optimal voltage between DBT and DM. According to these results, the use of higher voltage settings is not justified for the improvement of the image quality during a DBT examination.

  16. Development of Digital Steroscopic Imaging Technique in Mammography

    DTIC Science & Technology

    2001-05-01

    imaging technique in which the phantom was shifted instead of the focal spot for acquisition of the left-eye and right-eye images. In a preliminary observer... Phantoms (C) Phantom Evaluation of Full Field Steremammography (D) Evaluation of the Effect of Zooming on Depth Measurements in Digital...interpretation by radiologists and reduce unnecessary biopsies. To accomplish this goal, we first performed phantom studies to develop an optimal imaging

  17. X-ray light valve (XLV): a novel detectors' technology for digital mammography

    NASA Astrophysics Data System (ADS)

    Marcovici, Sorin; Sukhovatkin, Vlad; Oakham, Peter

    2014-03-01

    A novel method, based on X-ray Light Valve (XLV) technology, is proposed for making good image quality yet inexpensive flat panel detectors for digital mammography. The digital mammography markets, particularly in the developing countries, demand quality machines at substantially lower prices than the ones available today. Continuous pressure is applied on x-ray detectors' manufacturers to reduce the flat panel detectors' prices. XLV presents a unique opportunity to achieve the needed price - performance characteristics for direct conversion, x-ray detectors. The XLV based detectors combine the proven, superior, spatial resolution of a-Se with the simplicity and low cost of liquid crystals and optical scanning. The x-ray quanta absorbed by a 200 μm a-Se produce electron - hole pairs that move under an electric field to the top and bottom of a-Se layer. This 2D charge distribution creates at the interface with the liquid crystals a continuous (analog) charge image corresponding to the impinging radiation's information. Under the influence of local electrical charges next to them, the liquid crystals twist proportionally to the charges and vary their light reflectivity. A scanning light source illuminates the liquid crystals while an associated, pixilated photo-detector, having a 42 μm pixel size, captures the light reflected by the liquid crystals and converts it in16 bit words that are transmitted to the machine for image processing and display. The paper will describe a novel XLV, 25 cm x 30 cm, flat panel detector structure and its underlying physics as well as its preliminary performance measured on several engineering prototypes. In particular, the paper will present the results of measuring XLV detectors' DQE, MTF, dynamic range, low contrast resolution and dynamic behavior. Finally, the paper will introduce the new, low cost, XLV detector based, digital mammography machine under development at XLV Diagnostics Inc.

  18. Digital mammography in the radio-dense and complex pattern breast

    NASA Astrophysics Data System (ADS)

    Freedman, Matthew T.; Steller Artz, Dorothy E.; Jafroudi, Hamid; Hogge, Jacquelyn; Zuurbier, Rebecca A.; Lin, Jyh-Shyan; Katial, Raj; Mun, Seong K.

    1996-04-01

    The sensitivity of mammography for the detection of breast cancer is decreased in the radiodense breast. Storage phosphor digital radiographic systems have a wider latitude of exposure than conventional mammographic screen film systems. By using low resolution histogram equalization one can produce a mammographic image of the breast that retains the high frequency information that defines the edges of microcalcifications, architectural distortion and some masses but which, at the same time, allows one to look through into regions of increased breast radiodensity and identify microcalcifications within them. This paper demonstrates the effect of this special form of image processing.

  19. Teaching syllabus for radiological aspects of breast cancer screening with digital mammography.

    PubMed

    Van Ongeval, Chantal; Van Steen, André; Bosmans, Hilde

    2008-01-01

    The purpose of this study is to discuss the content of our new accreditation programme for radiologists' reading digital mammograms in a screening setting and to report our first experience with the new course. The course consisted of a theoretical part, given by the medical physicist, and a practical part given by the radiologist. The practical session is closely linked with the theoretical part and a reading session. The material is fully digital and can be presented on different platforms. In practice, the need for parallel soft-copy reading sessions on high-end workstations limits the number of participants. A high level of interactivity was noted between teacher and participant, with a thorough discussion of different digital mammography systems during a single teaching course. The main challenge for the teacher turned out to be the collection of representative material and the continuous updating of the material: new systems, processing techniques and artefacts need to be included regularly.

  20. [Full-field digital mammography with amorphous silicon-based flat- panel detector: physical imaging characteristics and signal detection].

    PubMed

    Ideguchi, Tadamitsu; Higashida, Yoshiharu; Himuro, Kazuhiko; Ohki, Masafumi; Nakamura, Satoru; Yoshida, Akira; Takagi, Rie; Hatano, Hirohide; Kuwahara, Rie; Toyonaga, Makiko; Tanaka, Isamu; Toyofuku, Fukai

    2004-03-01

    The physical characteristics of a clinical amorphous silicon-based flat-panel imager for full-field digital mammography were investigated. Pre-sampled modulation transfer functions (MTF) were measured by using a slit method. Noise power spectra were determined for different input exposures by fast Fourier transform. The MTFs of full-field digital mammography systems showed significantly higher values than those of the computed radiography (CR) system. The full-field digital mammography system showed a lower noise level than that of the CR system under the same exposure conditions. Contrast detail analysis has been performed to compare the detectability of the full-field digital mammography system with that of the screen-film (Min-R 2000/Min-R 2000) system. The average contrast-detail curves of digital and film images were obtained from the results of observation. Image quality figures (IQF) were also calculated from the individual observer performance tests. The results indicated that the digital contrast-detail curves and IQF, on average, are superior to those of the screen-film system.

  1. The simulation of 3D microcalcification clusters in 2D digital mammography and breast tomosynthesis

    SciTech Connect

    Shaheen, Eman; Van Ongeval, Chantal; Zanca, Federica; Cockmartin, Lesley; Marshall, Nicholas; Jacobs, Jurgen; Young, Kenneth C.; Dance, David R.; Bosmans, Hilde

    2011-12-15

    Purpose: This work proposes a new method of building 3D models of microcalcification clusters and describes the validation of their realistic appearance when simulated into 2D digital mammograms and into breast tomosynthesis images. Methods: A micro-CT unit was used to scan 23 breast biopsy specimens of microcalcification clusters with malignant and benign characteristics and their 3D reconstructed datasets were segmented to obtain 3D models of microcalcification clusters. These models were then adjusted for the x-ray spectrum used and for the system resolution and simulated into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. Six radiologists were asked to distinguish between 40 real and 40 simulated clusters of microcalcifications in two separate studies on 2D mammography and tomosynthesis datasets. Receiver operating characteristic (ROC) analysis was used to test the ability of each observer to distinguish between simulated and real microcalcification clusters. The kappa statistic was applied to assess how often the individual simulated and real microcalcification clusters had received similar scores (''agreement'') on their realistic appearance in both modalities. This analysis was performed for all readers and for the real and the simulated group of microcalcification clusters separately. ''Poor'' agreement would reflect radiologists' confusion between simulated and real clusters, i.e., lesions not systematically evaluated in both modalities as either simulated or real, and would therefore be interpreted as a success of the present models. Results: The area under the ROC curve, averaged over the observers, was 0.55 (95% confidence interval [0.44, 0.66]) for the 2D study, and 0.46 (95% confidence interval [0.29, 0.64]) for the tomosynthesis study, indicating no statistically significant difference between real and simulated

  2. National Performance Benchmarks for Modern Screening Digital Mammography: Update from the Breast Cancer Surveillance Consortium.

    PubMed

    Lehman, Constance D; Arao, Robert F; Sprague, Brian L; Lee, Janie M; Buist, Diana S M; Kerlikowske, Karla; Henderson, Louise M; Onega, Tracy; Tosteson, Anna N A; Rauscher, Garth H; Miglioretti, Diana L

    2016-12-05

    Purpose To establish performance benchmarks for modern screening digital mammography and assess performance trends over time in U.S. community practice. Materials and Methods This HIPAA-compliant, institutional review board-approved study measured the performance of digital screening mammography interpreted by 359 radiologists across 95 facilities in six Breast Cancer Surveillance Consortium (BCSC) registries. The study included 1 682 504 digital screening mammograms performed between 2007 and 2013 in 792 808 women. Performance measures were calculated according to the American College of Radiology Breast Imaging Reporting and Data System, 5th edition, and were compared with published benchmarks by the BCSC, the National Mammography Database, and performance recommendations by expert opinion. Benchmarks were derived from the distribution of performance metrics across radiologists and were presented as 50th (median), 10th, 25th, 75th, and 90th percentiles, with graphic presentations using smoothed curves. Results Mean screening performance measures were as follows: abnormal interpretation rate (AIR), 11.6 (95% confidence interval [CI]: 11.5, 11.6); cancers detected per 1000 screens, or cancer detection rate (CDR), 5.1 (95% CI: 5.0, 5.2); sensitivity, 86.9% (95% CI: 86.3%, 87.6%); specificity, 88.9% (95% CI: 88.8%, 88.9%); false-negative rate per 1000 screens, 0.8 (95% CI: 0.7, 0.8); positive predictive value (PPV) 1, 4.4% (95% CI: 4.3%, 4.5%); PPV2, 25.6% (95% CI: 25.1%, 26.1%); PPV3, 28.6% (95% CI: 28.0%, 29.3%); cancers stage 0 or 1, 76.9%; minimal cancers, 57.7%; and node-negative invasive cancers, 79.4%. Recommended CDRs were achieved by 92.1% of radiologists in community practice, and 97.1% achieved recommended ranges for sensitivity. Only 59.0% of radiologists achieved recommended AIRs, and only 63.0% achieved recommended levels of specificity. Conclusion The majority of radiologists in the BCSC surpass cancer detection recommendations for screening

  3. Cost-effectiveness of digital mammography screening before the age of 50 in The Netherlands.

    PubMed

    Sankatsing, Valérie D V; Heijnsdijk, Eveline A M; van Luijt, Paula A; van Ravesteyn, Nicolien T; Fracheboud, Jacques; de Koning, Harry J

    2015-10-15

    In the Netherlands, routine mammography screening starts at age 50. This starting age may have to be reconsidered because of the increasing breast cancer incidence among women aged 40 to 49 and the recent implementation of digital mammography. We assessed the cost-effectiveness of digital mammography screening that starts between age 40 and 49, using a microsimulation model. Women were screened before age 50, in addition to the current programme (biennial 50-74). Screening strategies varied in starting age (between 40 and 50) and frequency (annual or biennial). The numbers of breast cancers diagnosed, life-years gained (LYG) and breast cancer deaths averted were predicted and incremental cost-effectiveness ratios (ICERs) were calculated to compare screening scenarios. Biennial screening from age 50 to 74 (current strategy) was estimated to gain 157 life years per 1,000 women with lifelong follow-up, compared to a situation without screening, and cost €3,376/LYG (3.5% discounted). Additional screening increased the number of LYG, compared to no screening, ranging from 168 to 242. The costs to generate one additional LYG (i.e., ICER), comparing a screening strategy to the less intensive alternative, were estimated at €5,329 (biennial 48-74 vs. current strategy), €7,628 (biennial 45-74 vs. biennial 48-74), €10,826 (biennial 40-74 vs. biennial 45-74) and €18,759 (annual 40-49 + biennial 50-74 vs. biennial 40-74). Other strategies (49 + biennial 50-74 and annual 45-49 + biennial 50-74) resulted in less favourable ICERs. These findings show that extending the Dutch screening programme by screening between age 40 and 49 is cost-effective, particularly for biennial strategies.

  4. Comparison of digital breast tomosynthesis and 2D digital mammography using a hybrid performance test

    NASA Astrophysics Data System (ADS)

    Cockmartin, Lesley; Marshall, Nicholas W.; Van Ongeval, Chantal; Aerts, Gwen; Stalmans, Davina; Zanca, Federica; Shaheen, Eman; De Keyzer, Frederik; Dance, David R.; Young, Kenneth C.; Bosmans, Hilde

    2015-05-01

    This paper introduces a hybrid method for performing detection studies in projection image based modalities, based on image acquisitions of target objects and patients. The method was used to compare 2D mammography and digital breast tomosynthesis (DBT) in terms of the detection performance of spherical densities and microcalcifications. The method starts with the acquisition of spheres of different glandular equivalent densities and microcalcifications of different sizes immersed in a homogeneous breast tissue simulating medium. These target objects are then segmented and the subsequent templates are fused in projection images of patients and processed or reconstructed. This results in hybrid images with true mammographic anatomy and clinically relevant target objects, ready for use in observer studies. The detection study of spherical densities used 108 normal and 178 hybrid 2D and DBT images; 156 normal and 321 hybrid images were used for the microcalcifications. Seven observers scored the presence/absence of the spheres/microcalcifications in a square region via a 5-point confidence rating scale. Detection performance in 2D and DBT was compared via ROC analysis with sub-analyses for the density of the spheres, microcalcification size, breast thickness and z-position. The study was performed on a Siemens Inspiration tomosynthesis system using patient acquisitions with an average age of 58 years and an average breast thickness of 53 mm providing mean glandular doses of 1.06 mGy (2D) and 2.39 mGy (DBT). Study results showed that breast tomosynthesis (AUC = 0.973) outperformed 2D (AUC = 0.831) for the detection of spheres (p  <  0.0001) and this applied for all spherical densities and breast thicknesses. By way of contrast, DBT was worse than 2D for microcalcification detection (AUC2D = 0.974, AUCDBT = 0.838, p  <  0.0001), with significant differences found for all sizes (150-354 µm), for breast thicknesses above 40 mm and for heights

  5. Comparison of digital breast tomosynthesis and 2D digital mammography using a hybrid performance test.

    PubMed

    Cockmartin, Lesley; Marshall, Nicholas W; Van Ongeval, Chantal; Aerts, Gwen; Stalmans, Davina; Zanca, Federica; Shaheen, Eman; De Keyzer, Frederik; Dance, David R; Young, Kenneth C; Bosmans, Hilde

    2015-05-21

    This paper introduces a hybrid method for performing detection studies in projection image based modalities, based on image acquisitions of target objects and patients. The method was used to compare 2D mammography and digital breast tomosynthesis (DBT) in terms of the detection performance of spherical densities and microcalcifications. The method starts with the acquisition of spheres of different glandular equivalent densities and microcalcifications of different sizes immersed in a homogeneous breast tissue simulating medium. These target objects are then segmented and the subsequent templates are fused in projection images of patients and processed or reconstructed. This results in hybrid images with true mammographic anatomy and clinically relevant target objects, ready for use in observer studies. The detection study of spherical densities used 108 normal and 178 hybrid 2D and DBT images; 156 normal and 321 hybrid images were used for the microcalcifications. Seven observers scored the presence/absence of the spheres/microcalcifications in a square region via a 5-point confidence rating scale. Detection performance in 2D and DBT was compared via ROC analysis with sub-analyses for the density of the spheres, microcalcification size, breast thickness and z-position. The study was performed on a Siemens Inspiration tomosynthesis system using patient acquisitions with an average age of 58 years and an average breast thickness of 53 mm providing mean glandular doses of 1.06 mGy (2D) and 2.39 mGy (DBT). Study results showed that breast tomosynthesis (AUC = 0.973) outperformed 2D (AUC = 0.831) for the detection of spheres (p  <  0.0001) and this applied for all spherical densities and breast thicknesses. By way of contrast, DBT was worse than 2D for microcalcification detection (AUC2D = 0.974, AUCDBT = 0.838, p  <  0.0001), with significant differences found for all sizes (150-354 µm), for breast thicknesses above 40 mm and for heights

  6. Performance evaluation of image processing algorithms in digital mammography

    NASA Astrophysics Data System (ADS)

    Zanca, Federica; Van Ongeval, Chantal; Jacobs, Jurgen; Pauwels, Herman; Marchal, Guy; Bosmans, Hilde

    2008-03-01

    The purpose of the study is to evaluate the performance of different image processing algorithms in terms of representation of microcalcification clusters in digital mammograms. Clusters were simulated in clinical raw ("for processing") images. The entire dataset of images consisted of 200 normal mammograms, selected out of our clinical routine cases and acquired with a Siemens Novation DR system. In 100 of the normal images a total of 142 clusters were simulated; the remaining 100 normal mammograms served as true negative input cases. Both abnormal and normal images were processed with 5 commercially available processing algorithms: Siemens OpView1 and Siemens OpView2, Agfa Musica1, Sectra Mamea AB Sigmoid and IMS Raffaello Mammo 1.2. Five observers were asked to locate and score the cluster(s) in each image, by means of dedicated software tool. Observer performance was assessed using the JAFROC Figure of Merit. FROC curves, fitted using the IDCA method, have also been calculated. JAFROC analysis revealed significant differences among the image processing algorithms in the detection of microcalcifications clusters (p=0.0000369). Calculated average Figures of Merit are: 0.758 for Siemens OpView2, 0.747 for IMS Processing 1.2, 0.736 for Agfa Musica1 processing, 0.706 for Sectra Mamea AB Sigmoid processing and 0.703 for Siemens OpView1. This study is a first step towards a quantitative assessment of image processing in terms of cluster detection in clinical mammograms. Although we showed a significant difference among the image processing algorithms, this method does not on its own allow for a global performance ranking of the investigated algorithms.

  7. Effect of image quality on calcification detection in digital mammography

    PubMed Central

    Warren, Lucy M.; Mackenzie, Alistair; Cooke, Julie; Given-Wilson, Rosalind M.; Wallis, Matthew G.; Chakraborty, Dev P.; Dance, David R.; Bosmans, Hilde; Young, Kenneth C.

    2012-01-01

    Purpose: This study aims to investigate if microcalcification detection varies significantly when mammographic images are acquired using different image qualities, including: different detectors, dose levels, and different image processing algorithms. An additional aim was to determine how the standard European method of measuring image quality using threshold gold thickness measured with a CDMAM phantom and the associated limits in current EU guidelines relate to calcification detection. Methods: One hundred and sixty two normal breast images were acquired on an amorphous selenium direct digital (DR) system. Microcalcification clusters extracted from magnified images of slices of mastectomies were electronically inserted into half of the images. The calcification clusters had a subtle appearance. All images were adjusted using a validated mathematical method to simulate the appearance of images from a computed radiography (CR) imaging system at the same dose, from both systems at half this dose, and from the DR system at quarter this dose. The original 162 images were processed with both Hologic and Agfa (Musica-2) image processing. All other image qualities were processed with Agfa (Musica-2) image processing only. Seven experienced observers marked and rated any identified suspicious regions. Free response operating characteristic (FROC) and ROC analyses were performed on the data. The lesion sensitivity at a nonlesion localization fraction (NLF) of 0.1 was also calculated. Images of the CDMAM mammographic test phantom were acquired using the automatic setting on the DR system. These images were modified to the additional image qualities used in the observer study. The images were analyzed using automated software. In order to assess the relationship between threshold gold thickness and calcification detection a power law was fitted to the data. Results: There was a significant reduction in calcification detection using CR compared with DR: the alternative FROC

  8. Effect of image quality on calcification detection in digital mammography

    SciTech Connect

    Warren, Lucy M.; Mackenzie, Alistair; Cooke, Julie; Given-Wilson, Rosalind M.; Wallis, Matthew G.; Chakraborty, Dev P.; Dance, David R.; Bosmans, Hilde; Young, Kenneth C.

    2012-06-15

    Purpose: This study aims to investigate if microcalcification detection varies significantly when mammographic images are acquired using different image qualities, including: different detectors, dose levels, and different image processing algorithms. An additional aim was to determine how the standard European method of measuring image quality using threshold gold thickness measured with a CDMAM phantom and the associated limits in current EU guidelines relate to calcification detection. Methods: One hundred and sixty two normal breast images were acquired on an amorphous selenium direct digital (DR) system. Microcalcification clusters extracted from magnified images of slices of mastectomies were electronically inserted into half of the images. The calcification clusters had a subtle appearance. All images were adjusted using a validated mathematical method to simulate the appearance of images from a computed radiography (CR) imaging system at the same dose, from both systems at half this dose, and from the DR system at quarter this dose. The original 162 images were processed with both Hologic and Agfa (Musica-2) image processing. All other image qualities were processed with Agfa (Musica-2) image processing only. Seven experienced observers marked and rated any identified suspicious regions. Free response operating characteristic (FROC) and ROC analyses were performed on the data. The lesion sensitivity at a nonlesion localization fraction (NLF) of 0.1 was also calculated. Images of the CDMAM mammographic test phantom were acquired using the automatic setting on the DR system. These images were modified to the additional image qualities used in the observer study. The images were analyzed using automated software. In order to assess the relationship between threshold gold thickness and calcification detection a power law was fitted to the data. Results: There was a significant reduction in calcification detection using CR compared with DR: the alternative FROC

  9. Use of prior mammograms in the transition to digital mammography: a performance and cost analysis.

    PubMed

    Taylor-Phillips, S; Wallis, M G; Duncan, A; Gale, A G

    2012-01-01

    Breast screening in Europe is gradually changing from film to digital imaging and reporting of cases. In the transition period prior mammograms (from the preceding screening round) are films thereby potentially causing difficulties in comparison to current digital mammograms. To examine this breast screening performance was measured at a digital mammography workstation with prior mammograms displayed in different formats, and the associated costs calculated. 160 selected difficult cases (41% malignant) were read by eight UK qualified mammography readers in three conditions: with film prior mammograms; with digitised prior mammograms; or without prior mammograms. Lesion location and probability of malignancy were recorded, alongside a decision of whether to recall each case for further tests. JAFROC analysis showed a difference between conditions (p=.006); performance with prior mammograms in either film or digitised formats was superior to that without prior mammograms (p<.05). There was no difference in the performance when the prior mammograms were presented in film or digitised form. The number of benign or normal cases recalled was 26% higher without prior mammograms than with digitised or film prior mammograms (p<.05). This would correspond to an increase in recall rate at the study hospital from 4.3% to 5.5% with no associated increase in cancer detection rate. The cost of this increase was estimated to be £11,581 (€13,666) per 10,000 women screened, which is higher than the cost of digitised (£11,114/€13,115), or film display (£6451/€7612) of the prior mammograms. It is recommended that, where available, prior mammograms are used in the transition to digital breast screening.

  10. Image quality assessment in digital mammography: part I. Technical characterization of the systems

    NASA Astrophysics Data System (ADS)

    Marshall, N. W.; Monnin, P.; Bosmans, H.; Bochud, F. O.; Verdun, F. R.

    2011-07-01

    In many European countries, image quality for digital x-ray systems used in screening mammography is currently specified using a threshold-detail detectability method. This is a two-part study that proposes an alternative method based on calculated detectability for a model observer: the first part of the work presents a characterization of the systems. Eleven digital mammography systems were included in the study; four computed radiography (CR) systems, and a group of seven digital radiography (DR) detectors, composed of three amorphous selenium-based detectors, three caesium iodide scintillator systems and a silicon wafer-based photon counting system. The technical parameters assessed included the system response curve, detector uniformity error, pre-sampling modulation transfer function (MTF), normalized noise power spectrum (NNPS) and detective quantum efficiency (DQE). Approximate quantum noise limited exposure range was examined using a separation of noise sources based upon standard deviation. Noise separation showed that electronic noise was the dominant noise at low detector air kerma for three systems; the remaining systems showed quantum noise limited behaviour between 12.5 and 380 µGy. Greater variation in detector MTF was found for the DR group compared to the CR systems; MTF at 5 mm-1 varied from 0.08 to 0.23 for the CR detectors against a range of 0.16-0.64 for the DR units. The needle CR detector had a higher MTF, lower NNPS and higher DQE at 5 mm-1 than the powder CR phosphors. DQE at 5 mm-1 ranged from 0.02 to 0.20 for the CR systems, while DQE at 5 mm-1 for the DR group ranged from 0.04 to 0.41, indicating higher DQE for the DR detectors and needle CR system than for the powder CR phosphor systems. The technical evaluation section of the study showed that the digital mammography systems were well set up and exhibiting typical performance for the detector technology employed in the respective systems.

  11. Initial Image Quality and Clinical Experience with New CR Digital Mammography System: A Phantom and Clinical Study

    SciTech Connect

    Gaona, Enrique; Enriquez, Jesus Gabriel Franco; Alfonso, Beatriz Y. Alvarez; Castellanos, Gustavo Casian

    2008-08-11

    The goal of the study was to evaluate the first CR digital mammography system ( registered Konica-Minolta) in Mexico in clinical routine for cancer detection in a screening population and to determine if high resolution CR digital imaging is equivalent to state-of-the-art screen-film imaging. The mammograms were evaluated by two observers with cytological or histological confirmation for BIRADS 3, 4 and 5. Contrast, exposure and artifacts of the images were evaluated. Different details like skin, retromamillary space and parenchymal structures were judged. The detectability of microcalcifications and lesions were compared and correlated to histology. The difference in sensitivity of CR Mammography (CRM) and Screen Film Mammography (SFM) was not statistically significant. However, CRM had a significantly lower recall rate, and the lesion detection was equal or superior to conventional images. There is no significant difference in the number of microcalcifications and highly suspicious calcifications were equally detected on both film-screen and digital images. Different anatomical regions were better detectable in digital than in conventional mammography.

  12. Determination of mass attenuation coefficients for threshold contrast evaluation in digital mammography

    NASA Astrophysics Data System (ADS)

    Hummel, Johann; Semturs, Friedrich; Menhart, Susanne; Figl, Michael

    2010-04-01

    According to the 'European protocol for the quality control of the physical and technical aspects of mammography screening' (EPQC) image quality digital mammography units has to be evaluated at different breast thicknesses. At the standard thickness of 50 mm polymethyl methacrylate (PMMA) image quality is determined by the analysis of CDMAM contrast detail phantom images where threshold contrasts are calculated for different gold disc diameters. To extend these results to other breast thicknesses contrast-to-noise ratios (CNR) and threshold contrast (TC) visibilities have to be calculated for all required thicknesses. To calculate the latter the mass attenuation coefficient (MAC) of gold has to be known for all possible beam qualities in the tube voltage range between 26 and 32 kV. In this paper we first determined the threshold contrast visibility using the CDMAM phantom with the same beam quality at different current-time products (mAs). We can derive from Rose theory that CNR • CT • α = const, where α is the diameter of the gold cylinder. From this the corresponding attenuation coefficients can be calculated. This procedure was repeated for four different beam qualities (Mo/Mo 27kV, Rh/Rh 29kV, Rh/Rh 31 kV, and W/Rh 29 kV)). Next, we measured the aluminium half value layer (HVL) of all x-ray spectra relevant for mammography. Using a first order Taylor expansion of MAC as a function of HVL, all other desired MAC can be calculated. The MAC as a function of the HVL was derived to MAChvl = -286.97 * hvl+186.03 with R2 = 0.997, where MAChvl indicates the MAC for all specific x-ray spectrum defined by its aluminium half value layer. Based on this function all necessary MACs needed for quality assurance (QA) were calculated. The results were in good agreement with the data found in the protocol.

  13. Validation of simulation of calcifications for observer studies in digital mammography

    NASA Astrophysics Data System (ADS)

    Warren, L. M.; Green, F. H.; Shrestha, L.; Mackenzie, A.; Dance, D. R.; Young, K. C.

    2013-08-01

    Studies using simulated calcifications can be performed to measure the effect of different imaging factors on calcification detection in digital mammography. The simulated calcifications must be inserted into clinical images with realistic contrast and sharpness. MoCa is a program which modifies the contrast and sharpness of simulated calcification clusters extracted from images of mastectomy specimens acquired on a digital specimen cabinet at high magnification for insertion into clinical mammography images. This work determines whether the use of MoCa results in simulated calcifications with the correct contrast and sharpness. Aluminium foils (thickness 0.1-0.4 mm) and 1.60 µm thick gold discs (diameter 0.13-0.8 mm) on 0.5 mm aluminium were imaged with a range of thicknesses of polymethyl methacrylate (PMMA) using an amorphous selenium direct digital (DR) system and a powder phosphor computed radiography (CR) system (real images). Simulated images of the tests objects were also generated using MoCa. The contrast of the aluminium squares and the degradation of the contrast of the gold discs as a function of disc diameter were compared in the real and simulated images. The average ratios of the simulated-to-real aluminium contrasts over all aluminium and PMMA thicknesses were 1.03±0.04 (two standard errors in the mean) and 0.99±0.03 for the DR and CR systems, respectively. The ratio of the simulated-to-real degradations of contrast averaged over all disc diameters and PMMA thicknesses were 1.007±0.008 and 1.002±0.013 for DR and CR, respectively. The use of MoCa was accurate within the experimental errors.

  14. Experience in reading digital images may decrease observer accuracy in mammography

    NASA Astrophysics Data System (ADS)

    Rawashdeh, Mohammad A.; Lewis, Sarah J.; Lee, Warwick; Mello-Thoms, Claudia; Reed, Warren M.; McEntee, Mark; Tapia, Kriscia; Brennan, Patrick C.

    2015-03-01

    Rationale and Objectives: To identify parameters linked to higher levels of performance in screening mammography. In particular we explored whether experience in reading digital cases enhances radiologists' performance. Methods: A total of 60 cases were presented to the readers, of which 20 contained cancers and 40 showed no abnormality. Each case comprised of four images and 129 breast readers participated in the study. Each reader was asked to identify and locate any malignancies using a 1-5 confidence scale. All images were displayed using 5MP monitors, supported by radiology workstations with full image manipulation capabilities. A jack-knife free-response receiver operating characteristic, figure of merit (JAFROC, FOM) methodology was employed to assess reader performance. Details were obtained from each reader regarding their experience, qualifications and breast reading activities. Spearman and Mann Whitney U techniques were used for statistical analysis. Results: Higher performance was positively related to numbers of years professionally qualified (r= 0.18; P<0.05), number of years reading breast images (r= 0.24; P<0.01), number of mammography images read per year (r= 0.28; P<0.001) and number of hours reading mammographic images per week (r= 0.19; P<0.04). Unexpectedly, higher performance was inversely linked to previous experience with digital images (r= - 0.17; p<0.05) and further analysis, demonstrated that this finding was due to changes in specificity. Conclusion: This study suggests suggestion that readers with experience in digital images reporting may exhibit a reduced ability to correctly identify normal appearances requires further investigation. Higher performance is linked to number of cases read per year.

  15. Method for inserting noise in digital mammography to simulate reduction in radiation dose

    NASA Astrophysics Data System (ADS)

    Borges, Lucas R.; de Oliveira, Helder C. R.; Nunes, Polyana F.; Vieira, Marcelo A. C.

    2015-03-01

    The quality of clinical x-ray images is closely related to the radiation dose used in the imaging study. The general principle for selecting the radiation is ALARA ("as low as reasonably achievable"). The practical optimization, however, remains challenging. It is well known that reducing the radiation dose increases the quantum noise, which could compromise the image quality. In order to conduct studies about dose reduction in mammography, it would be necessary to acquire repeated clinical images, from the same patient, with different dose levels. However, such practice would be unethical due to radiation related risks. One solution is to simulate the effects of dose reduction in clinical images. This work proposes a new method, based on the Anscombe transformation, which simulates dose reduction in digital mammography by inserting quantum noise into clinical mammograms acquired with the standard radiation dose. Thus, it is possible to simulate different levels of radiation doses without exposing the patient to new levels of radiation. Results showed that the achieved quality of simulated images generated with our method is the same as when using other methods found in the literature, with the novelty of using the Anscombe transformation for converting signal-independent Gaussian noise into signal-dependent quantum noise.

  16. Breast cancer screening using tomosynthesis in combination with digital mammography compared to digital mammography alone: a cohort study within the PROSPR consortium.

    PubMed

    Conant, Emily F; Beaber, Elisabeth F; Sprague, Brian L; Herschorn, Sally D; Weaver, Donald L; Onega, Tracy; Tosteson, Anna N A; McCarthy, Anne Marie; Poplack, Steven P; Haas, Jennifer S; Armstrong, Katrina; Schnall, Mitchell D; Barlow, William E

    2016-02-01

    Digital breast tomosynthesis (DBT) is emerging as the new standard of care for breast cancer screening based on improved cancer detection coupled with reductions in recall compared to screening with digital mammography (DM) alone. However, many prior studies lack follow-up data to assess false negatives examinations. The purpose of this study is to assess if DBT is associated with improved screening outcomes based on follow-up data from tumor registries or pathology. Retrospective analysis of prospective cohort data from three research centers performing DBT screening in the PROSPR consortium from 2011 to 2014 was performed. Recall and biopsy rates were assessed from 198,881 women age 40-74 years undergoing screening (142,883 DM and 55,998 DBT examinations). Cancer, cancer detection, and false negative rates and positive predictive values were assessed on examinations with one year of follow-up. Logistic regression was used to compare DBT to DM adjusting for research center, age, prior breast imaging, and breast density. There was a reduction in recall with DBT compared to DM (8.7 vs. 10.4 %, p < 0.0001), with adjusted OR = 0.68 (95 % CI = 0.65-0.71). DBT demonstrated a statistically significant increase in cancer detection over DM (5.9 vs. 4.4/1000 screened, adjusted OR = 1.45, 95 % CI = 1.12-1.88), an improvement in PPV1 (6.4 % for DBT vs. 4.1 % for DM, adjusted OR = 2.02, 95 % CI = 1.54-2.65), and no significant difference in false negative rates for DBT compared to DM (0.46 vs. 0.60/1000 screened, p = 0.347). Our data support implementation of DBT screening based on increased cancer detection, reduced recall, and no difference in false negative screening examinations.

  17. Effective x-ray attenuation measurements with full field digital mammography

    SciTech Connect

    Heine, John J.; Behera, Madhusmita

    2006-11-15

    This work shows that effective x-ray attenuation coefficients may be estimated by applying Beer's Law to phantom image data acquired with the General Electric Senographe 2000D full field digital mammography system. Theoretical developments are provided indicating that an approximate form of the Beer's relation holds for polychromatic x-ray beams. The theoretical values were compared with experimentally determined measured values, which were estimated at various detector locations. The measured effective attenuation coefficients are in agreement with those estimated with theoretical developments and numerical integration. The work shows that the measured quantities show little spatial variation. The main ideas are demonstrated with polymethylmethacrylate and breast tissue equivalent phantom imaging experiments. The work suggests that the effective attenuation coefficients may be used as known values for radiometric standardization applications that compensate for the image acquisition influences. The work indicates that it is possible to make quantitative attenuation coefficient measurements from a system designed for clinical purposes.

  18. Analysis of the scatter effect on detective quantum efficiency of digital mammography

    NASA Astrophysics Data System (ADS)

    Park, Jiwoong; Yun, Seungman; Kim, Dong Woon; Baek, Cheol-Ha; Youn, Hanbean; Jeon, Hosang; Kim, Ho Kyung

    2016-03-01

    The scatter effect on detective quantum efficiency (DQE) of digital mammography is investigated using the cascaded-systems model. The cascaded-systems model includes a scatter-reduction device as a binomial selection stage. Quantum-noise-limited operation approximates the system DQE into the multiplication form of the scatter-reduction device DQE and the conventional detector DQE. The developed DQE model is validated in comparisons with the measured results using a CMOS flat-panel detector under scatter environments. For various scatter-reduction devices, the slot-scan method shows the best scatter-cleanup performance in terms of DQE, and the scatter-cleanup performance of the conventional one-dimensional grid is rather worse than the air gap. The developed model can also be applied to general radiography and will be very useful for a better design of imaging chain.

  19. The effect of image processing on the detection of cancers in digital mammography.

    PubMed

    Warren, Lucy M; Given-Wilson, Rosalind M; Wallis, Matthew G; Cooke, Julie; Halling-Brown, Mark D; Mackenzie, Alistair; Chakraborty, Dev P; Bosmans, Hilde; Dance, David R; Young, Kenneth C

    2014-08-01

    OBJECTIVE. The objective of our study was to investigate the effect of image processing on the detection of cancers in digital mammography images. MATERIALS AND METHODS. Two hundred seventy pairs of breast images (both breasts, one view) were collected from eight systems using Hologic amorphous selenium detectors: 80 image pairs showed breasts containing subtle malignant masses; 30 image pairs, biopsy-proven benign lesions; 80 image pairs, simulated calcification clusters; and 80 image pairs, no cancer (normal). The 270 image pairs were processed with three types of image processing: standard (full enhancement), low contrast (intermediate enhancement), and pseudo-film-screen (no enhancement). Seven experienced observers inspected the images, locating and rating regions they suspected to be cancer for likelihood of malignancy. The results were analyzed using a jackknife-alternative free-response receiver operating characteristic (JAFROC) analysis. RESULTS. The detection of calcification clusters was significantly affected by the type of image processing: The JAFROC figure of merit (FOM) decreased from 0.65 with standard image processing to 0.63 with low-contrast image processing (p = 0.04) and from 0.65 with standard image processing to 0.61 with film-screen image processing (p = 0.0005). The detection of noncalcification cancers was not significantly different among the image-processing types investigated (p > 0.40). CONCLUSION. These results suggest that image processing has a significant impact on the detection of calcification clusters in digital mammography. For the three image-processing versions and the system investigated, standard image processing was optimal for the detection of calcification clusters. The effect on cancer detection should be considered when selecting the type of image processing in the future.

  20. Digital magnification mammography with matched incident exposure: physical imaging properties and detectability of simulated microcalcifications.

    PubMed

    Tanaka, Nobukazu; Naka, Kentaro; Fukushima, Hiroko; Morishita, Junji; Toyofuku, Fukai; Ohki, Masafumi; Higashida, Yoshiharu

    2011-07-01

    Our purpose was to evaluate the usefulness of digital magnification mammography with matched incident exposure by investigating the physical imaging properties and doing an observer performance test. A computed radiography system and a mammographic unit were used in this study. Contact and magnification radiographies of 1.2-1.8 in combination with focal spot sizes of 0.1 mm without grid and 0.3 mm with grid were performed. Physical imaging properties, namely, scatter fraction, total modulation transfer function (MTF) including the presampled MTF and the MTF of focal spot size, and Wiener spectrum (WS), were measured. Detail visibility was evaluated by use of free-response receiver operating characteristic analysis of the detectability of simulated microcalcifications. Scatter fractions decreased considerably as the magnification factor increased without grid technique. In the grid technique, scatter fractions for all magnification techniques were comparable. The total MTFs of magnification techniques with a focal spot size of 0.1 mm improved significantly compared with the conventional contact technique. However, the improvement of the total MTFs of magnification techniques with the combination of 0.3 mm focal spot size was small. The WSs degraded with an increase of the magnification factor compared with the contact technique due to the maintained exposure incident on the object. The observer performance test indicated that the 1.8 magnification technique with the 0.1 mm focal spot size provided higher detectability than did the contact technique. Digital magnification mammography under the same incident exposure conditions improved the detectability of microcalcifications.

  1. [Analysis of Cost-effectiveness of screening for breast cancer with conventional mammography, digital and magnetic resonance imaging].

    PubMed

    Peregrino, Antonio Augusto de Freitas; Vianna, Cid Manso de Mello; de Almeida, Carlos Eduardo Veloso; Gonzáles, Gabriela Bittencourt; Machado, Samara Cristina Ferreira; Costa e Silva, Frances Valéria; Rodrigues, Marcus Paulo da Silva

    2012-01-01

    A cost-effectiveness analysis was conducted in screening for breast cancer. The use of conventional mammography, digital and magnetic resonance imaging were compared with natural disease history as a baseline. A Markov model projected breast cancer in a group of 100,000 women for a 30 year period, with screening every two years. Four distinct scenarios were modeled: (1) the natural history of breast cancer, as a baseline, (2) conventional film mammography, (3) digital mammography and (4) magnetic resonance imaging. The costs of the scenarios modeled ranged from R$ 194.216,68 for natural history, to R$ 48.614.338,31, for screening with magnetic resonance imaging. The difference in effectiveness between the interventions ranged from 300 to 78.000 years of life gained in the cohort. The ratio of incremental cost-effectiveness in terms of cost per life-year gains, conventional mammographic screening has produced an extra year for R$ 13.573,07. The ICER of magnetic resonance imaging was R$ 2.904.328,88, compared to no screening. In conclusion, it is more cost-effective to perform the screening with conventional mammography than other technological interventions.

  2. Impact of Computer-Aided Detection Systems on Radiologist Accuracy With Digital Mammography

    PubMed Central

    Cole, Elodia B.; Zhang, Zheng; Marques, Helga S.; Hendrick, R. Edward; Yaffe, Martin J.; Pisano, Etta D.

    2014-01-01

    OBJECTIVE The purpose of this study was to assess the impact of computer-aided detection (CAD) systems on the performance of radiologists with digital mammograms acquired during the Digital Mammographic Imaging Screening Trial (DMIST). MATERIALS AND METHODS Only those DMIST cases with proven cancer status by biopsy or 1-year follow-up that had available digital images were included in this multireader, multicase ROC study. Two commercially available CAD systems for digital mammography were used: iCAD SecondLook, version 1.4; and R2 ImageChecker Cenova, version 1.0. Fourteen radiologists interpreted, without and with CAD, a set of 300 cases (150 cancer, 150 benign or normal) on the iCAD SecondLook system, and 15 radiologists interpreted a different set of 300 cases (150 cancer, 150 benign or normal) on the R2 ImageChecker Cenova system. RESULTS The average AUC was 0.71 (95% CI, 0.66–0.76) without and 0.72 (95% CI, 0.67–0.77) with the iCAD system (p = 0.07). Similarly, the average AUC was 0.71 (95% CI, 0.66–0.76) without and 0.72 (95% CI 0.67–0.77) with the R2 system (p = 0.08). Sensitivity and specificity differences without and with CAD for both systems also were not significant. CONCLUSION Radiologists in our studies rarely changed their diagnostic decisions after the addition of CAD. The application of CAD had no statistically significant effect on radiologist AUC, sensitivity, or specificity performance with digital mammograms from DMIST. PMID:25247960

  3. Dose dependence of mass and microcalcification detection in digital mammography: free response human observer studies.

    PubMed

    Ruschin, Mark; Timberg, Pontus; Båth, Magnus; Hemdal, Bengt; Svahn, Tony; Saunders, Rob S; Samei, Ehsan; Andersson, Ingvar; Mattsson, Soren; Chakrabort, Dev P; Tingber, Anders

    2007-02-01

    The purpose of this study was to evaluate the effect of dose reduction in digital mammography on the detection of two lesion types-malignant masses and clusters of microcalcifications. Two free-response observer studies were performed-one for each lesion type. Ninety screening images were retrospectively selected; each image was originally acquired under automatic exposure conditions, corresponding to an average glandular dose of 1.3 mGy for a standard breast (50 mm compressed breast thickness with 50% glandularity). For each study, one to three simulated lesions were added to each of 40 images (abnormals) while 50 were kept without lesions (normals). Two levels of simulated system noise were added to the images yielding two new image sets, corresponding to simulated dose levels of 50% and 30% of the original images (100%). The manufacturer's standard display processing was subsequently applied to all images. Four radiologists experienced in mammography evaluated the images by searching for lesions and marking and assigning confidence levels to suspicious regions. The search data were analyzed using jackknife free-response (JA-FROC) methodology. For the detection of masses, the mean figure-of-merit (FOM) averaged over all readers was 0.74, 0.71, and 0.68 corresponding to dose levels of 100%, 50%, and 30%, respectively. These values were not statistically different from each other (F= 1.67, p=0.19) but showed a decreasing trend. In contrast, in the microcalcification study the mean FOM was 0.93, 0.67, and 0.38 for the same dose levels and these values were all significantly different from each other (F = 109.84, p < 0.0001). The results indicate that lowering the present dose level by a factor of two compromised the detection of microcalcifications but had a weaker effect on mass detection.

  4. Dose dependence of mass and microcalcification detection in digital mammography: Free response human observer studies

    SciTech Connect

    Ruschin, Mark; Timberg, Pontus; Ba ring th, Magnus; Hemdal, Bengt; Svahn, Tony; Saunders, Rob S.; Samei, Ehsan; Andersson, Ingvar; Mattsson, Soeren; Chakraborty, Dev P.; Tingberg, Anders

    2007-02-15

    The purpose of this study was to evaluate the effect of dose reduction in digital mammography on the detection of two lesion types--malignant masses and clusters of microcalcifications. Two free-response observer studies were performed--one for each lesion type. Ninety screening images were retrospectively selected; each image was originally acquired under automatic exposure conditions, corresponding to an average glandular dose of 1.3 mGy for a standard breast (50 mm compressed breast thickness with 50% glandularity). For each study, one to three simulated lesions were added to each of 40 images (abnormals) while 50 were kept without lesions (normals). Two levels of simulated system noise were added to the images yielding two new image sets, corresponding to simulated dose levels of 50% and 30% of the original images (100%). The manufacturer's standard display processing was subsequently applied to all images. Four radiologists experienced in mammography evaluated the images by searching for lesions and marking and assigning confidence levels to suspicious regions. The search data were analyzed using jackknife free-response (JAFROC) methodology. For the detection of masses, the mean figure-of-merit (FOM) averaged over all readers was 0.74, 0.71, and 0.68 corresponding to dose levels of 100%, 50%, and 30%, respectively. These values were not statistically different from each other (F=1.67, p=0.19) but showed a decreasing trend. In contrast, in the microcalcification study the mean FOM was 0.93, 0.67, and 0.38 for the same dose levels and these values were all significantly different from each other (F=109.84, p<0.0001). The results indicate that lowering the present dose level by a factor of two compromised the detection of microcalcifications but had a weaker effect on mass detection.

  5. A novel approach to background subtraction in contrast-enhanced dual-energy digital mammography with commercially available mammography devices: Polychromaticity correction

    SciTech Connect

    Contillo, Adriano Di Domenico, Giovanni; Cardarelli, Paolo; Gambaccini, Mauro; Taibi, Angelo

    2015-11-15

    Purpose: Contrast-enhanced digital mammography is an image subtraction technique that is able to improve the detectability of lesions in dense breasts. One of the main sources of error, when the technique is performed by means of commercial mammography devices, is represented by the intrinsic polychromaticity of the x-ray beams. The aim of the work is to propose an iterative procedure, which only assumes the knowledge of a small set of universal quantities, to take into account the polychromaticity and correct the subtraction results accordingly. Methods: In order to verify the procedure, it has been applied to an analytical simulation of a target containing a contrast medium and to actual radiographs of a breast phantom containing cavities filled with a solution of the same medium. Results: The reconstructed densities of contrast medium were compared, showing very good agreement between the theoretical predictions and the experimental results already after the first iteration. Furthermore, the convergence of the iterative procedure was studied, showing that only a small number of iterations is necessary to reach limiting values. Conclusions: The proposed procedure represents an efficient solution to the polychromaticity issue, qualifying therefore as a viable alternative to inverse-map functions.

  6. Mass detection in breast tomosynthesis and digital mammography: a model observer study

    NASA Astrophysics Data System (ADS)

    Castella, C.; Ruschin, M.; Eckstein, M. P.; Abbey, C. K.; Kinkel, K.; Verdun, F. R.; Tingberg, A.; Bochud, F. O.

    2009-02-01

    In this study, we adapt and apply model observers within the framework of realistic detection tasks in breast tomosynthesis (BT). We use images consisting of realistic masses digitally embedded in real patient anatomical backgrounds, and we adapt specific model observers that have been previously applied to digital mammography (DM). We design alternative forced-choice experiments (AFC) studies for DM and BT tasks in the signal known exactly but variable (SKEV) framework. We compare performance of various linear model observers (non-prewhitening matched filter with an eye filter, and several channelized Hotelling observers (CHO) against human. A good agreement in performance between human and model observers can be obtained when an appropriate internal noise level is adopted. Models achieve the same detection performance across BT and DM with about three times less projected signal intensity in BT than in DM (humans: 3.8), due to the anatomical noise reduction in BT. We suggest that, in the future, model observers can potentially be used as an objective tool for automating the optimization of BT acquisition parameters or reconstruction algorithms, or narrowing a wide span of possible parameter combinations, without requiring human observers studies.

  7. An alternative method for noise analysis using pixel variance as part of quality control procedures on digital mammography systems

    NASA Astrophysics Data System (ADS)

    Bouwman, R.; Young, K.; Lazzari, B.; Ravaglia, V.; Broeders, M.; van Engen, R.

    2009-11-01

    According to the European Guidelines for quality assured breast cancer screening and diagnosis, noise analysis is one of the measurements that needs to be performed as part of quality control procedures on digital mammography systems. However, the method recommended in the European Guidelines does not discriminate sufficiently between systems with and without additional noise besides quantum noise. This paper attempts to give an alternative and relatively simple method for noise analysis which can divide noise into electronic noise, structured noise and quantum noise. Quantum noise needs to be the dominant noise source in clinical images for optimal performance of a digital mammography system, and therefore the amount of electronic and structured noise should be minimal. For several digital mammography systems, the noise was separated into components based on the measured pixel value, standard deviation (SD) of the image and the detector entrance dose. The results showed that differences between systems exist. Our findings confirm that the proposed method is able to discriminate systems based on their noise performance and is able to detect possible quality problems. Therefore, we suggest to replace the current method for noise analysis as described in the European Guidelines by the alternative method described in this paper.

  8. The simulation of 3D mass models in 2D digital mammography and breast tomosynthesis

    SciTech Connect

    Shaheen, Eman De Keyzer, Frederik; Bosmans, Hilde; Ongeval, Chantal Van; Dance, David R.; Young, Kenneth C.

    2014-08-15

    Purpose: This work proposes a new method of building 3D breast mass models with different morphological shapes and describes the validation of the realism of their appearance after simulation into 2D digital mammograms and breast tomosynthesis images. Methods: Twenty-five contrast enhanced MRI breast lesions were collected and each mass was manually segmented in the three orthogonal views: sagittal, coronal, and transversal. The segmented models were combined, resampled to have isotropic voxel sizes, triangularly meshed, and scaled to different sizes. These masses were referred to as nonspiculated masses and were then used as nuclei onto which spicules were grown with an iterative branching algorithm forming a total of 30 spiculated masses. These 55 mass models were projected into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. The realism of the appearance of these mass models was assessed by five radiologists via receiver operating characteristic (ROC) analysis when compared to 54 real masses. All lesions were also given a breast imaging reporting and data system (BIRADS) score. The data sets of 2D mammography and tomosynthesis were read separately. The Kendall's coefficient of concordance was used for the interrater observer agreement assessment for the BIRADS scores per modality. Further paired analysis, using the Wilcoxon signed rank test, of the BIRADS assessment between 2D and tomosynthesis was separately performed for the real masses and for the simulated masses. Results: The area under the ROC curves, averaged over all observers, was 0.54 (95% confidence interval [0.50, 0.66]) for the 2D study, and 0.67 (95% confidence interval [0.55, 0.79]) for the tomosynthesis study. According to the BIRADS scores, the nonspiculated and the spiculated masses varied in their degrees of malignancy from normal (BIRADS 1) to highly

  9. Image quality of a prototype direct conversion detector for digital mammography

    NASA Astrophysics Data System (ADS)

    Mainprize, James G.; Ford, Nancy L.; Yin, Shi; Tumer, Tumay O.; Yaffe, Martin J.

    1999-05-01

    A digital mammography system in which the x-ray sensitive device is a solid-state direct conversion detector is under development. This detector is a 1 mm thick silicon photodiode array hybridized to a CCD read-out, with a 50 micrometer pixel pitch. The detector is designed to be used in a slot-scanned system using time-delay integration (TDI) for signal acquisition. To handle the large signal generated in the photodiode, a novel read-out technique was used, in which charge was integrated 'on-chip' over a small number of rows, and the output of each of these sections was digitally summed 'off-chip' to produce the total integrated signal for each pixel in the image. This two-stage integration process not only allows easy acquisition of large signals, it effectively increases bit depth from 12 bits (for a single section) to approximately 16 (for the total integrated signal). The image quality of the device has been measured and compared to predictions based on cascaded linear systems theory. The resolution of the new detector was determined from the modulation transfer function (MTF) which was obtained from over-sampled edge spread functions (ESF). The ESF was measured in both the scan and slot directions from four repeated images of a tantalum edge. Noise power spectra (NPS) were determined from 40 repeated flat-field images at each of several x-ray exposures. By combining the MTF and NPS measurements, the detective quantum efficiency (DQE) was also determined. The MTF in the non-scanned direction was found to greater than 20% at 10 mm-1 and slightly lower in the scanned direction (approximately equals 10% at 10 mm-1). In all cases, the DQE was at least comparable to film-screen mammography receptors. The DQE at 120 mR detector exposure at zero spatial frequency ranged from 0.4 to 0.6 depending on the sample tested. Electronic noise was fairly low, contributing to less than plus or minus 7 ADU (out of a possible 98304 ADU). Future work will involve re-designing the

  10. Method for simulating dose reduction in digital mammography using the Anscombe transformation

    PubMed Central

    Borges, Lucas R.; de Oliveira, Helder C. R.; Nunes, Polyana F.; Bakic, Predrag R.; Maidment, Andrew D. A.; Vieira, Marcelo A. C.

    2016-01-01

    Purpose: This work proposes an accurate method for simulating dose reduction in digital mammography starting from a clinical image acquired with a standard dose. Methods: The method developed in this work consists of scaling a mammogram acquired at the standard radiation dose and adding signal-dependent noise. The algorithm accounts for specific issues relevant in digital mammography images, such as anisotropic noise, spatial variations in pixel gain, and the effect of dose reduction on the detective quantum efficiency. The scaling process takes into account the linearity of the system and the offset of the detector elements. The inserted noise is obtained by acquiring images of a flat-field phantom at the standard radiation dose and at the simulated dose. Using the Anscombe transformation, a relationship is created between the calculated noise mask and the scaled image, resulting in a clinical mammogram with the same noise and gray level characteristics as an image acquired at the lower-radiation dose. Results: The performance of the proposed algorithm was validated using real images acquired with an anthropomorphic breast phantom at four different doses, with five exposures for each dose and 256 nonoverlapping ROIs extracted from each image and with uniform images. The authors simulated lower-dose images and compared these with the real images. The authors evaluated the similarity between the normalized noise power spectrum (NNPS) and power spectrum (PS) of simulated images and real images acquired with the same dose. The maximum relative error was less than 2.5% for every ROI. The added noise was also evaluated by measuring the local variance in the real and simulated images. The relative average error for the local variance was smaller than 1%. Conclusions: A new method is proposed for simulating dose reduction in clinical mammograms. In this method, the dependency between image noise and image signal is addressed using a novel application of the Anscombe

  11. Technology transfer in digital mammography. Report of the Joint National Cancer Institute-National Aeronautics and Space Administration workshop of May 19-20, 1993.

    PubMed

    Winfield, D; Silbiger, M; Brown, G S; Clarke, L; Dwyer, S; Yaffe, M; Shtern, F

    1994-04-01

    Digital mammography is one of the most promising novel technologies for further improvement of early detection of breast cancer, offering important potential advantages: 1) improved image quality; 2) digital image processing for improved lesion contrast; 3) computer-aided diagnosis for enhanced radiologic interpretation; and 4) teleradiology for facilitated radiologic consultation. The Diagnostic Imaging Research Branch of the National Cancer Institute (NCI) recently funded an international, multidisciplinary, multi-institutional Digital Mammography Development Group for collaborations between NCI, the academic community, and industry to facilitate the integrated development and implementation of digital mammographic systems. Currently, however, digital mammography faces a number of fundamental technological roadblocks: 1) cost-effective digital detectors and displays for imaging systems; 2) the need for novel algorithms for image processing and computer-aided diagnosis; and 3) high performance, low cost digital networks to provide an "information superhighway" for teleradiology. To solve some of these technological problems, the Diagnostic Imaging Research Branch of NCI joined efforts with the Technology Transfer Division of the National Aeronautics and Space Administration to pursue a federal technology transfer program in digital mammography. The authors discuss the findings and recommendations of the workshop entitled "Technology Transfer in Digital Mammography," which was organized and held jointly by the NCI and the National Aeronautics and Space Administration in May, 1993. Numerous innovative technologies of varying degree of promise for digital mammography were presented at the conference. In this article, specific technologies presented at the workshop by the federal and federally-supported laboratories are described, and critiques of these technologies by the leaders of the medical imaging community are presented.

  12. A slot-scanned photodiode-array/CCD hybrid detector for digital mammography.

    PubMed

    Mainprize, James G; Ford, Nancy L; Yin, Shi; Tümer, Türmay; Yaffe, Martin J

    2002-02-01

    We have developed a novel direct conversion detector for use in a slot-scanning digital mammography system. The slot-scan concept allows for dose efficient scatter rejection and the ability to use small detectors to produce a large-area image. The detector is a hybrid design with a 1.0 mm thick silicon PIN photodiode array (the x-ray absorber) indium-bump bonded to a CCD readout that is operated in time-delay integration (TDI) mode. Because the charge capacity requirement for good image quality exceeds the capabilities of standard CCDs, a novel CCD was developed. This CCD consists of 24 independent sections, each acting as a miniature CCD with eight rows for TDI. The signal from each section is combined off-chip to produce a full signal image. The MTF and DQE for the device was measured at several exposures and compared to a linear systems model of signal and noise propagation. Because of the scanning nature of TDI imaging, both the MTF(f) and DQE(f) are reduced along the direction of the scanning motion. For a 26 kVp spectrum, the DQE(0) was measured to be 0.75+/-0.02 for an exposure of 1.29 x 10(-5) C/kg (50 mR).

  13. Shape determination of microcalcifications in simulated digital mammography images with varying pixel size

    NASA Astrophysics Data System (ADS)

    Ruschin, Mark; Bath, Magnus; Hemdal, Bengt; Tingberg, Anders

    2005-04-01

    The purpose of this work was to study how the pixel size of digital detectors can affect shape determination of microcalcifications in mammography. Screen-film mammograms containing microcalcifications clinically proven to be indicative of malignancy were digitised at 100 lines/mm using a high-resolution Tango drum scanner. Forty microcalcifications were selected to cover an appropriate range of sizes, shapes and contrasts typically found of malignant cases. Based on the measured MTF and NPS of the combined screen-film and scanner system, these digitised images were filtered to simulate images acquired with a square sampling pixel size of 10 μm x 10 μm and a fill factor of one. To simulate images acquired with larger pixel sizes, these finely sampled images were re-binned to yield a range of effective pixel sizes from 20 μm up to 140 μm. An alternative forced-choice (AFC) observer experiment was conducted with eleven observers for this set of digitised microcalcifications to determine how pixel size affects the ability to discriminate shape. It was found that observer score increased with decreasing pixel size down to 60 μm (p<0.01), at which point no significant advantage was obtained by using smaller pixel sizes due to the excessive relative noise-per-pixel. The relative gain in shape discrimination ability at smaller pixel sizes was larger for microcalcifications that were smaller than 500 μm and circular.

  14. Steerable dyadic wavelet transform and interval wavelets for enhancement of digital mammography

    NASA Astrophysics Data System (ADS)

    Laine, Andrew F.; Koren, Iztok; Yang, Wuhai; Taylor, Fred J.

    1995-04-01

    This paper describes two approaches for accomplishing interactive feature analysis by overcomplete multiresolution representations. We show quantitatively that transform coefficients, modified by an adaptive non-linear operator, can make more obvious unseen or barely seen features of mammography without requiring additional radiation. Our results are compared with traditional image enhancement techniques by measuring the local contrast of known mammographic features. We design a filter bank representing a steerable dyadic wavelet transform that can be used for multiresolution analysis along arbitrary orientations. Digital mammograms are enhanced by orientation analysis performed by a steerable dyadic wavelet transform. Arbitrary regions of interest (ROI) are enhanced by Deslauriers-Dubuc interpolation representations on an interval. We demonstrate that our methods can provide radiologists with an interactive capability to support localized processing of selected (suspicion) areas (lesions). Features extracted from multiscale representations can provide an adaptive mechanism for accomplishing local contrast enhancement. By improving the visualization of breast pathology can improve changes of early detection while requiring less time to evaluate mammograms for most patients.

  15. Accelerating Monte Carlo image reconstruction of a PMMA phantom through variance reduction techniques for quality control in digital mammography.

    PubMed

    Ramos, M; Ferrer, S; Verdu, G

    2005-01-01

    Mammography is a non-invasive technique used for the detection of breast lesions. The use of this technique in a breast screening program requires a continuous quality control testing in mammography units for ensuring a minimum absorbed glandular dose without modifying image quality. Digital mammography has been progressively introduced in screening centers, since recent evolution of photostimulable phosphor detectors. The aim of this work is the validation of a methodology for reconstructing digital images of a polymethyl-methacrylate (PMMA) phantom (P01 model) under pure Monte Carlo techniques. A reference image has been acquired for this phantom under automatic exposure control (AEC) mode (28 kV and 14 mAs). Some variance reduction techniques (VRT) have been applied to improve the efficiency of the simulations, defined as the number of particles reaching the imaging system per starting particle. All images have been used and stored in DICOM format. The results prove that the signal-to-noise ratio (SNR) of the reconstructed images have been increased with the use of the VRT, showing similar values between different employed tallies. As a conclusion, these images could be used during quality control testing for showing any deviation of the exposition parameters from the desired reference level.

  16. First results with real-time selenium-based full-field digital mammography three-dimensional imaging system

    NASA Astrophysics Data System (ADS)

    Lehtimaki, Mari; Pamilo, Martti; Raulisto, Leena; Kalke, Martti

    2004-05-01

    Our goal in this paper is to evaluate the capability of real-time selenium-technology-based full-field digital mammography (FFDM) system in breast tomosynthesis. The objective of this study is to find out the present status of amorphous selenium technology in the sense of advanced applications in clinical use. We were using tuned aperture computed tomography (TACT+) 3-dimensional (3D) technology for reconstruction. Under evaluation were amorphous selenium signal-to-noise-ratio, flat panel image artefacts and acquisition time to perform full-field digital mammography 3D examination. To be able to validate the system we used a special breast phantom. We found out that 3D imaging technology provides diagnostic value and benefits over 2-dimensional (2D) imaging. 3D TACT advantages are to define if mammography finding is caused by a real abnormal lesion or by superposition of normal parenchymal structures, to be able to diagnose and analyze the findings properly, to detect changes in breast tissue which would otherwise be missed, to verify the possible multifocality of the breast cancers, to verify the correct target for biopsies and to reduce number of biopsies performed. Slice visualization and 3D volume model provide greater diagnostic information compared to 2D projection screening and diagnostic imaging.

  17. Monte Carlo derivation of filtered tungsten anode X-ray spectra for dose computation in digital mammography*

    PubMed Central

    Paixão, Lucas; Oliveira, Bruno Beraldo; Viloria, Carolina; de Oliveira, Marcio Alves; Teixeira, Maria Helena Araújo; Nogueira, Maria do Socorro

    2015-01-01

    Objective Derive filtered tungsten X-ray spectra used in digital mammography systems by means of Monte Carlo simulations. Materials and Methods Filtered spectra for rhodium filter were obtained for tube potentials between 26 and 32 kV. The half-value layer (HVL) of simulated filtered spectra were compared with those obtained experimentally with a solid state detector Unfors model 8202031-H Xi R/F & MAM Detector Platinum and 8201023-C Xi Base unit Platinum Plus w mAs in a Hologic Selenia Dimensions system using a direct radiography mode. Results Calculated HVL values showed good agreement as compared with those obtained experimentally. The greatest relative difference between the Monte Carlo calculated HVL values and experimental HVL values was 4%. Conclusion The results show that the filtered tungsten anode X-ray spectra and the EGSnrc Monte Carlo code can be used for mean glandular dose determination in mammography. PMID:26811553

  18. On image quality metrics and the usefulness of grids in digital mammography

    PubMed Central

    Chen, Han; Danielsson, Mats; Xu, Cheng; Cederström, Björn

    2015-01-01

    Abstract. Antiscatter grids are used in digital mammography to reduce the scattered radiation from the breast and improve image contrast. They are, however, imperfect and lead to partial absorption of primary radiation, as well as failing to absorb all scattered radiation. Nevertheless, the general consensus has been that antiscatter grids improve image quality for the majority of breast types and sizes. There is, however, inconsistency in the literature, and recent results show that a substantial image quality improvement can be achieved even for thick breasts if the grid is disposed of. The purpose of this study was to investigate if differences in the considered imaging task and experimental setup could explain the different outcomes. We estimated the dose reduction that can be achieved if the grid were to be removed as a function of breast thickness with varying geometries and experimental conditions. Image quality was quantified by the signal-difference-to-noise ratio (SDNR) measured using an aluminum (Al) filter on blocks of poly(methyl methacrylate) (PMMA), and images were acquired with and without grid at a constant exposure. We also used a theoretical model validated with Monte Carlo simulations. Both theoretically and experimentally, the main finding was that when a large 4×8  cm2 Al filter was used, the SDNR values for the gridless images were overestimated up to 25% compared to the values for the small 1×1  cm2 filter, and gridless imaging was superior for any PMMA thickness. For the small Al filter, gridless imaging was only superior for PMMAs thinner than 4 cm. This discrepancy can be explained by a different sensitivity to and sampling of the angular scatter spread function, depending on the size of the contrast object. The experimental differences were eliminated either by using a smaller region of interest close to the edge of the large filter or by applying a technique of scatter correction by subtracting the estimated scatter image

  19. Diagnostic accuracy of digital mammography versus tomosynthesis: effect of radiologists' experience

    NASA Astrophysics Data System (ADS)

    Zanca, F.; Wallis, M.; Moa, E.; Leifland, K.; Danielsson, M.; Oyen, R.; Bosmans, H.

    2012-02-01

    Purpose: To investigate whether readers' experience affects performance in a study comparing 2D digital mammography (2D) with 2-view (CC and MLO) or 1-view (MLO) tomosynthesis. Materials and Methods: One-hundred-thirty 2D cases were collected from screening assessment and referral clinics; 64 of the cases had verified abnormalities and the remaining were confirmed normal. Two-view tomosynthesis images were obtained from the same patients. Ten accredited readers (5 with >= 10 years experience in mammography and 5 with < 10 years) classified the cases in terms of malignancy (rate 0-5), and recall (yes/no), for both modalities. A second experiment was performed with the same cases, with 10 other readers (again 5 experienced / 5 less experienced), but using 2D and 1-view tomosynthesis as the two modalities. The multi-reader-multi-case ROC method was applied and the significance of diagnostic accuracy difference of 2D vs tomosynthesis was calculated, as a function of experience and for each experiment. Recall rate (RR) on malignant and benign cases was also calculated, along with reading time. Results: No significant difference was reached between 2D and 2-view tomosynthesis for experienced readers (pvalue= 0.25); for less experienced readers the p-value was significant (0.03). No significant difference was found between 2D and 1-view tomosynthesis, independent of readers' experience. RR for benign cases decreased for tomosynthesis (for booth 1- and 2-view), independent of experience. Average reading time per case was 79 s (range 65- 91 s) and 134 s (range 119-158 s) for experienced readers; 56 s (range 46-67 s) and 115s (range 97-142 s) for nonexperienced, for 2D and 2-view tomosynthesis respectively. Reading time was 74 s (range 43-98 s) and 99 s (range 73- 117 s) for experienced readers; 74 s (range 62-85 s) and 94 s (range 82-137 s) for non-experienced, for 2D and 1-view tomosynthesis respectively. Conclusions: For experienced readers, there is no evidence of

  20. Effect of filter on average glandular dose and image quality in digital mammography

    NASA Astrophysics Data System (ADS)

    Songsaeng, C.; Krisanachinda, A.; Theerakul, K.

    2016-03-01

    To determine the average glandular dose and entrance surface air kerma in both phantoms and patients to assess image quality for different target-filters (W/Rh and W/Ag) in digital mammography system. The compressed breast thickness, compression force, average glandular dose, entrance surface air kerma, peak kilovoltage and tube current time were recorded and compared between W/Rh and W/Ag target filter. The CNR and the figure of merit were used to determine the effect of target filter on image quality. The mean AGD of the W/Rh target filter was 1.75 mGy, the mean ESAK was 6.67 mGy, the mean CBT was 54.1 mm, the mean CF was 14 1bs. The mean AGD of W/Ag target filter was 2.7 mGy, the mean ESAK was 12.6 mGy, the mean CBT was 75.5 mm, the mean CF was 15 1bs. In phantom study, the AGD was 1.2 mGy at 4 cm, 3.3 mGy at 6 cm and 3.83 mGy at 7 cm thickness. The FOM was 24.6, CNR was 9.02 at thickness 6 cm. The FOM was 18.4, CNR was 8.6 at thickness 7 cm. The AGD from Digital Mammogram system with W/Rh of thinner CBT was lower than the AGD from W/Ag target filter.

  1. Free software for performing physical analysis of systems for digital radiography and mammography

    SciTech Connect

    Donini, Bruno; Lanconelli, Nico; Rivetti, Stefano; Bertolini, Marco

    2014-05-15

    Purpose: In this paper, the authors present a free software for assisting users in achieving the physical characterization of x-ray digital systems and image quality checks. Methods: The program was developed as a plugin of a well-known public-domain suite ImageJ. The software can assist users in calculating various physical parameters such as the response curve (also termed signal transfer property), modulation transfer function (MTF), noise power spectra (NPS), and detective quantum efficiency (DQE). It also includes the computation of some image quality checks: defective pixel analysis, uniformity, dark analysis, and lag. Results: The software was made available in 2009 and has been used during the last couple of years by many users who gave us valuable feedback for improving its usability. It was tested for achieving the physical characterization of several clinical systems for digital radiography and mammography. Various published papers made use of the outcomes of the plugin. Conclusions: This software is potentially beneficial to a variety of users: physicists working in hospitals, staff working in radiological departments, such as medical physicists, physicians, engineers. The plugin, together with a brief user manual, are freely available and can be found online ( http://www.medphys.it/downloads.htm ). With our plugin users can estimate all three most important parameters used for physical characterization (MTF, NPS, and also DQE). The plugin can run on any operating system equipped with ImageJ suite. The authors validated the software by comparing MTF and NPS curves on a common set of images with those obtained with other dedicated programs, achieving a very good agreement.

  2. Addition of Digital Breast Tomosynthesis to Full-Field Digital Mammography in the Diagnostic Setting: Additional Value and Cancer Detectability

    PubMed Central

    Seo, Mirinae; Kim, Sun Ah; Kim, Won Hwa; Lim, Ji He; Lee, Su Hyun; Bae, Min Sun; Koo, Hye Ryoung; Cho, Nariya; Moon, Woo Kyung

    2016-01-01

    Purpose The purpose of this study was to assess the value of adding digital breast tomosynthesis (DBT) to full-field digital mammography (FFDM) in the diagnostic workup of breast cancer and to determine which lesion variables affect cancer detectability in the combined modality. Methods Between March and May 2012, paired FFDM and DBT images were obtained from 203 women as part of a diagnostic workup for breast cancer. Images from FFDM alone, DBT alone, and DBT combined with FFDM were reviewed in separate sessions by six blinded readers. Jackknife alternative free-response receiver operating characteristic (JAFROC) figure of merit (FOM), sensitivity, and specificity were compared between the modalities. Lesion characteristics affecting the cancer detection rate when using the combined modality were also analyzed. Results Among the 203 women, 126 women had a total of 129 malignancies and 77 women had total of 77 benign lesions. The overall JAFROC FOM of the combined modality was higher than that of FFDM alone (0.827 vs. 0.775, p<0.001) and that of DBT alone was higher than that of FFDM alone (0.807 vs. 0.775, p=0.027). The overall sensitivity of the combined modality was higher than that of FFDM alone (80.0% vs. 73.2%, p<0.001) and that of DBT alone was higher than that of FFDM alone (78.3% vs. 73.2%, p=0.007). Compared to FFDM alone, the combined modality detected an additional 48 cancers. Using the combined modality, the presence of masses or microcalcifications was significantly associated with the cancer detection rate (p<0.001). Conclusion The combination of DBT with FFDM results in a higher diagnostic yield than FFDM alone. Additionally, DBT alone performs better than FFDM alone. However, even when DBT is combined with FFDM, breast cancers with no discernible masses and those lacking calcifications are difficult to detect. PMID:28053633

  3. Digital breast tomosynthesis: application of 2D digital mammography CAD to detection of microcalcification clusters on planar projection image

    NASA Astrophysics Data System (ADS)

    Samala, Ravi K.; Chan, Heang-Ping; Lu, Yao; Hadjiiski, Lubomir; Wei, Jun; Helvie, Mark

    2015-03-01

    Computer-aided detection (CAD) has the potential to aid radiologists in detection of microcalcification clusters (MCs). CAD for digital breast tomosynthesis (DBT) can be developed by using the reconstructed volume, the projection views or other derivatives as input. We have developed a novel method of generating a single planar projection (PPJ) image from a regularized DBT volume to emphasize the high contrast objects such as microcalcifications while removing the anatomical background and noise. In this work, we adapted a CAD system developed for digital mammography (CADDM) to the PPJ image and compared its performance with our CAD system developed for DBT volumes (CADDBT) in the same set of cases. For microcalcification detection in the PPJ image using the CADDM system, the background removal preprocessing step designed for DM was not needed. The other methods and processing steps in the CADDM system were kept without modification while the parameters were optimized with a training set. The linear discriminant analysis classifier using cluster based features was retrained to generate a discriminant score to be used as decision variable. For view-based FROC analysis, at 80% sensitivity, an FP rate of 1.95/volume and 1.54/image were achieved, respectively, for CADDBT and CADDM in an independent test set. At a threshold of 1.2 FPs per image or per DBT volume, the nonparametric analysis of the area under the FROC curve shows that the optimized CADDM for PPJ is significantly better than CADDBT. However, the performance of CADDM drops at higher sensitivity or FP rate, resulting in similar overall performance between the two CAD systems. The higher sensitivity of the CADDM in the low FP rate region and vice versa for the CADDBT indicate that a joint CAD system combining detection in the DBT volume and the PPJ image has the potential to increase the sensitivity and reduce the FP rate.

  4. Tools and methods for exposure control optimization in digital mammography in presence of texture

    NASA Astrophysics Data System (ADS)

    Grosjean, Bénédicte; Muller, Serge; Souchay, Henri

    2007-03-01

    To accurately detect radiological signs of cancer, mammography requires the best possible image quality for a target patient dose. The application of automatic optimization of parameters (AOP) to digital systems has been improved recently. The metric used to derive this AOP was based on the expected CNR of calcium material in a uniform background. In this work, we use a new metric, based on the detection performance of an a-contrario observer on lesions in simulated images. Breast images at various thicknesses and glandularity levels were simulated with flat and textured backgrounds. Various exposure spectra (Mo/Mo, Mo/Rh and Rh/Rh anode/filter materials, kVp ranging from 25 to 33 kV) were considered. The tube output has been normalized in order to obtain comparable AGD values for each image of a given breast over the various acquisition techniques. Images were scored with the a-contrario observer, the performance criterion being the minimal lesion size needed to reach a given detection threshold. The optimal spectra are found similar to those delivered by the AOP in both flat and textured backgrounds. The choice of the anode/filter combination appears to be more critical than kVp adjustments in particular for the thicker breasts. Our approach also yields an estimate of the detection variability due to texture signal. We found that the anatomical structure variability cannot be overcome by beam quality optimization of the current system in presence of complex background, which confirms the potential benefit of any imaging technology reducing the variability of detection due to texture.

  5. A CdZnTe slot-scanned detector for digital mammography.

    PubMed

    Mainprize, James G; Ford, Nancy L; Yin, Shi; Gordon, Eli E; Hamilton, William J; Tümer, Tümay O; Yaffe, Martin J

    2002-12-01

    A new high-resolution detector has been developed for use in a slot-scanned digital mammography system. The detector is a hybrid device that consists of a CCD operating in time-delay integration mode that is bonded to a 150-microm-thick CdZnTe photoconductor array. The CCD was designed with a detector element pitch of 50 microm. Two devices were evaluated with differing crystalline quality. Incomplete charge collection was a source of reduction in DQE. This occurs in both devices due to characteristically low mobility-lifetime products for CdZnTe, with the greatest losses demonstrated by the multicrystalline sample. The mobility-lifetime products for the multicrystalline device were found to be 2.4 x 10(-4) and 4.0 x 10(-7) cm2/V for electrons and holes, respectively. The device constructed with higher quality single crystal CdZnTe demonstrated mobility-lifetime products of 1.0 x 10(-4) and 4.4 x 10(-6) cm2/V for electrons and holes. The MTF and DQE for the device were measured at several exposures and results were compared to predictions from a linear systems model of signal and noise propagation. The MTF at a spatial frequency of 10 mm(-1) exceeded 0.18 and 0.56 along the scan and slot directions, respectively. Scanning motion and CCD design limited the resolution along the scan direction. For an x-ray beam from a tungsten target tube with 40 microm molybdenum filtration operated at 26 kV, the single crystal device demonstrated a DQE(0) of 0.70 +/- 0.02 at 7.1 x 10(-6) C/kg (27 mR) exposure to the detector, despite its relatively poor charge collection efficiency.

  6. Digital mammography--DQE versus optimized image quality in clinical environment: an on site study

    NASA Astrophysics Data System (ADS)

    Oberhofer, Nadia; Fracchetti, Alessandro; Springeth, Margareth; Moroder, Ehrenfried

    2010-04-01

    The intrinsic quality of the detection system of 7 different digital mammography units (5 direct radiography DR; 2 computed radiography CR), expressed by DQE, has been compared with their image quality/dose performances in clinical use. DQE measurements followed IEC 62220-1-2 using a tungsten test object for MTF determination. For image quality assessment two different methods have been applied: 1) measurement of contrast to noise ratio (CNR) according to the European guidelines and 2) contrast-detail (CD) evaluation. The latter was carried out with the phantom CDMAM ver. 3.4 and the commercial software CDMAM Analyser ver. 1.1 (both Artinis) for automated image analysis. The overall image quality index IQFinv proposed by the software has been validated. Correspondence between the two methods has been shown figuring out a linear correlation between CNR and IQFinv. All systems were optimized with respect to image quality and average glandular dose (AGD) within the constraints of automatic exposure control (AEC). For each equipment, a good image quality level was defined by means of CD analysis, and the corresponding CNR value considered as target value. The goal was to achieve for different PMMA-phantom thicknesses constant image quality, that means the CNR target value, at minimum dose. All DR systems exhibited higher DQE and significantly better image quality compared to CR systems. Generally switching, where available, to a target/filter combination with an x-ray spectrum of higher mean energy permitted dose savings at equal image quality. However, several systems did not allow to modify the AEC in order to apply optimal radiographic technique in clinical use. The best ratio image quality/dose was achieved by a unit with a-Se detector and W anode only recently available on the market.

  7. A comparison of calibration data from full field digital mammography units for breast density measurements

    PubMed Central

    2013-01-01

    Background Breast density is a significant breast cancer risk factor measured from mammograms. The most appropriate method for measuring breast density for risk applications is still under investigation. Calibration standardizes mammograms to account for acquisition technique differences prior to making breast density measurements. We evaluated whether a calibration methodology developed for an indirect x-ray conversion full field digital mammography (FFDM) technology applies to direct x-ray conversion FFDM systems. Methods Breast tissue equivalent (BTE) phantom images were used to establish calibration datasets for three similar direct x-ray conversion FFDM systems. The calibration dataset for each unit is a function of the target/filter combination, x-ray tube voltage, current × time (mAs), phantom height, and two detector fields of view (FOVs). Methods were investigated to reduce the amount of calibration data by restricting the height, mAs, and FOV sampling. Calibration accuracy was evaluated with mixture phantoms. We also compared both intra- and inter-system calibration characteristics and accuracy. Results Calibration methods developed previously apply to direct x-ray conversion systems with modification. Calibration accuracy was largely within the acceptable range of ± 4 standardized units from the ideal value over the entire acquisition parameter space for the direct conversion units. Acceptable calibration accuracy was maintained with a cubic-spline height interpolation, representing a modification to previous work. Calibration data is unit specific, can be acquired with the large FOV, and requires a minimum of one reference mAs sample. The mAs sampling, calibration accuracy, and the necessity for machine specific calibration data are common characteristics and in agreement with our previous work. Conclusion The generality of our calibration approach was established under ideal conditions. Evaluation with patient data using breast cancer status

  8. Comparison of signal to noise ratios from spatial and frequency domain formulations of nonprewhitening model observers in digital mammography

    SciTech Connect

    Sisini, Francesco; Zanca, Federica; Marshall, Nicholas W.; Taibi, Angelo; Cardarelli, Paolo; Bosmans, Hilde

    2012-09-15

    Purpose: Image quality indices based upon model observers are promising alternatives to laborious human readings of contrast-detail images. This is especially appealing in digital mammography as limiting values for contrast thresholds determine, according to some international protocols, the acceptability of these systems in the radiological practice. The objective of the present study was to compare the signal to noise ratios (SNR) obtained with two nonprewhitening matched filter model observer approaches, one in the spatial domain and the other in the frequency domain, and with both of them worked out for disks as present in the CDMAM phantom. Methods: The analysis was performed using images acquired with the Siemens Novation and Inspiration digital mammography systems. The spatial domain formulation uses a series of high dose CDMAM images as the signal and a routine exposure of two flood images to calculate the covariance matrix. The frequency domain approach uses the mathematical description of a disk and modulation transfer function (MTF) and noise power spectrum (NPS) calculated from images. Results: For both systems most of the SNR values calculated in the frequency domain were in very good agreement with the SNR values calculated in the spatial domain. Both the formulations in the frequency domain and in the spatial domain show a linear relationship between SNR and the diameter of the CDMAM discs. Conclusions: The results suggest that both formulations of the model observer lead to very similar figures of merit. This is a step forward in the adoption of figures of merit based on NPS and MTF for the acceptance testing of mammography systems.

  9. Effect of image processing version on detection of non-calcification cancers in 2D digital mammography imaging

    NASA Astrophysics Data System (ADS)

    Warren, L. M.; Cooke, J.; Given-Wilson, R. M.; Wallis, M. G.; Halling-Brown, M.; Mackenzie, A.; Chakraborty, D. P.; Bosmans, H.; Dance, D. R.; Young, K. C.

    2013-03-01

    Image processing (IP) is the last step in the digital mammography imaging chain before interpretation by a radiologist. Each manufacturer has their own IP algorithm(s) and the appearance of an image after IP can vary greatly depending upon the algorithm and version used. It is unclear whether these differences can affect cancer detection. This work investigates the effect of IP on the detection of non-calcification cancers by expert observers. Digital mammography images for 190 patients were collected from two screening sites using Hologic amorphous selenium detectors. Eighty of these cases contained non-calcification cancers. The images were processed using three versions of IP from Hologic - default (full enhancement), low contrast (intermediate enhancement) and pseudo screen-film (no enhancement). Seven experienced observers inspected the images and marked the location of regions suspected to be non-calcification cancers assigning a score for likelihood of malignancy. This data was analysed using JAFROC analysis. The observers also scored the clinical interpretation of the entire case using the BSBR classification scale. This was analysed using ROC analysis. The breast density in the region surrounding each cancer and the number of times each cancer was detected were calculated. IP did not have a significant effect on the radiologists' judgment of the likelihood of malignancy of individual lesions or their clinical interpretation of the entire case. No correlation was found between number of times each cancer was detected and the density of breast tissue surrounding that cancer.

  10. Design and image-quality performance of high resolution CMOS-based X-ray imaging detectors for digital mammography

    NASA Astrophysics Data System (ADS)

    Cha, B. K.; Kim, J. Y.; Kim, Y. J.; Yun, S.; Cho, G.; Kim, H. K.; Seo, C.-W.; Jeon, S.; Huh, Y.

    2012-04-01

    In digital X-ray imaging systems, X-ray imaging detectors based on scintillating screens with electronic devices such as charge-coupled devices (CCDs), thin-film transistors (TFT), complementary metal oxide semiconductor (CMOS) flat panel imagers have been introduced for general radiography, dental, mammography and non-destructive testing (NDT) applications. Recently, a large-area CMOS active-pixel sensor (APS) in combination with scintillation films has been widely used in a variety of digital X-ray imaging applications. We employed a scintillator-based CMOS APS image sensor for high-resolution mammography. In this work, both powder-type Gd2O2S:Tb and a columnar structured CsI:Tl scintillation screens with various thicknesses were fabricated and used as materials to convert X-ray into visible light. These scintillating screens were directly coupled to a CMOS flat panel imager with a 25 × 50 mm2 active area and a 48 μm pixel pitch for high spatial resolution acquisition. We used a W/Al mammographic X-ray source with a 30 kVp energy condition. The imaging characterization of the X-ray detector was measured and analyzed in terms of linearity in incident X-ray dose, modulation transfer function (MTF), noise-power spectrum (NPS) and detective quantum efficiency (DQE).

  11. Analysis of the detective quantum efficiency of a developmental detector for digital mammography.

    PubMed

    Williams, M B; Simoni, P U; Smilowitz, L; Stanton, M; Phillips, W; Stewart, A

    1999-11-01

    We are developing a modular detector for applications in full field digital mammography and for diagnostic breast imaging. The detector is based on a design that has been refined over the past decade for applications in x-ray crystallography [Kalata et al., Proc. SPIE 1345, 270-279 (1990); Phillips et al. ibid. 2009, 133-138 (1993), Phillips et al., Nucl. Instrum. Methods Phys. Rev. A 334, 621-630 (1993)]. The full field mammographic detector, currently undergoing clinical evaluation, is formed from a 19 cm x 28 cm phosphor screen, read out by a 2 x 3 array of butted charge-coupled device (CCD) modules. Each 2k x 2k CCD is optically coupled to the phosphor via a fiber optic taper with dimensions of 9.4 cm x 9.4cm at the phosphor. This paper describes the imaging performance of a two-module prototype, built using a similar design. In this paper we use cascaded linear systems analysis to develop a model for calculating the spatial frequency dependent noise power spectrum (NPS) and detective quantum efficiency (DQE) of the detector using the measured modulation transfer function (MTF). We compare results of the calculation with the measured NPS and DQE of the prototype. Calculated and measured DQEs are compared over a range of clinically relevant x-ray exposures and kVps. We find that for x-ray photon energies between 10 and 28 keV, the detector gain ranges between 2.5 and 3.7 CCD electrons per incident x-ray, or approximately 5-8 electrons per absorbed x ray. Using a Mo/Mo beam and acrylic phantom, over a detector entrance exposure range of approximately 10 to 80 mR, the volume under the measured 2-d NPS of the prototype detector is proportional to the x-ray exposure, indicating quantum limited performance. Substantial agreement between the calculated and measured values was obtained for the frequency and exposure dependent NPS and DQE over a range of tube voltage from 25 to 30 kVp.

  12. Imaging performance of a clinical selenium flat-panel detector for advanced applications in full-field digital mammography

    NASA Astrophysics Data System (ADS)

    Loustauneau, Vincent; Bissonnette, Michel; Cadieux, Sebastien; Hansroul, Marc; Masson, E.; Savard, Serge; Polischuk, Brad T.; Lehtimauki, Mari J.

    2003-06-01

    The advent of digital detectors will enable several advanced imaging applications to be used in the fight against breast cancer. For example, dynamic imaging applications such as tomosynthesis, contrast enhanced and dual energy mammography have demonstrated promising results. In this paper, we will assess the suitability of this detector for these advanced applications. MTF and DQE measurements were performed on a selenium FFDM detector to assess image quality. Ghosting properties of a digital detector are also an important factor, since it can strongly degrade image quality. In this paper, we will also report on the ghosting characteristics of the selenium detector, using typical exposures envisioned to be used in tomosynthesis exams. The physical mechanisms that create ghost images will be discussed and will be quantified.

  13. Breast cancer detection and classification in digital mammography based on Non-Subsampled Contourlet Transform (NSCT) and Super Resolution.

    PubMed

    Pak, Fatemeh; Kanan, Hamidreza Rashidy; Alikhassi, Afsaneh

    2015-11-01

    Breast cancer is one of the most perilous diseases among women. Breast screening is a method of detecting breast cancer at a very early stage which can reduce the mortality rate. Mammography is a standard method for the early diagnosis of breast cancer. In this paper, a new algorithm is proposed for breast cancer detection and classification in digital mammography based on Non-Subsampled Contourlet Transform (NSCT) and Super Resolution (SR). The presented algorithm includes three main parts including pre-processing, feature extraction and classification. In the pre-processing stage, after determining the region of interest (ROI) by an automatic technique, the quality of image is improved using NSCT and SR algorithm. In the feature extraction part, several features of the image components are extracted and skewness of each feature is calculated. Finally, AdaBoost algorithm is used to classify and determine the probability of benign and malign disease. The obtained results on Mammographic Image Analysis Society (MIAS) database indicate the significant performance and superiority of the proposed method in comparison with the state of the art approaches. According to the obtained results, the proposed technique achieves 91.43% and 6.42% as a mean accuracy and FPR, respectively.

  14. Computer-aided detection of masses in full-field digital mammography using screen-film mammograms for training.

    PubMed

    Kallenberg, Michiel; Karssemeijer, Nico

    2008-12-07

    It would be of great value when available databases of screen-film mammography (SFM) images can be used to train full-field digital mammography (FFDM) computer-aided detection (CAD) systems, as compilation of new databases is costly. In this paper, we investigate this possibility. Firstly, we develop a method that converts an FFDM image into an SFM-like representation. In this conversion method, we establish a relation between exposure and optical density by simulation of an automatic exposure control unit. Secondly, we investigate the effects of using the SFM images as training samples compared to training with FFDM images. Our FFDM database consisted of 266 cases, of which 102 were biopsy-proven malignant masses and 164 normals. The images were acquired with systems of two different manufacturers. We found that, when we trained our FFDM CAD system with a small number of images, training with FFDM images, using a five-fold crossvalidation procedure, outperformed training with SFM images. However, when the full SFM database, consisting of 348 abnormal cases (including 204 priors) and 810 normal cases, was used for training, SFM training outperformed FFDMA training. These results show that an existing CAD system for detection of masses in SFM can be used for FFDM images without retraining.

  15. Design of linear anti-scatter grid geometry with optimum performance for screen-film and digital mammography systems

    NASA Astrophysics Data System (ADS)

    Khodajou-Chokami, H.; Sohrabpour, M.

    2015-08-01

    A detailed 3D Monte Carlo simulation of the grid geometrical parameters in screen-film mammography (SFM) and digital mammography (DM) systems has been performed. A combination of IEC 60627:2013 international standard conditions and other more clinically relevant parameters were used for this simulation. Accuracy of our results has been benchmarked with previously published data and good agreement has been obtained. Calculations in a wide range of linear anti-scatter grid geometries have been carried out. The evaluated parameters for the SFM system were the Bucky factor (BF) and contrast improvement factor (CIF) and for the DM system it was signal difference-to-noise ratio improvement factor (SIF). The CIF parameter was chosen to be nearly the same as the commercial grade, the BF and SIF were significantly improved compared to commercial grids in use today. Our optimized grid parameters for the SFM system were lead strip thickness d=12  µm, grid ratio r= 5 and strip density N=65 lines/cm. And for the DM system these parameters were d= 5  µm, r = 3 and N=100 lines/cm. Both optimized grid sets have thinner d and higher N compared to the commercial grids.

  16. Task specific evaluation of clinical full field digital mammography systems using the Fourier definition of the Hotelling observer SNR

    NASA Astrophysics Data System (ADS)

    Liu, Haimo; Badano, Aldo; Benevides, Luis; Chakrabarti, Kish; Kaczmarek, Richard V.; Kyprianou, Iacovos S.

    2010-04-01

    Pixel Signal to Noise Ratio (SNR) is a commonly used clinical metric for evaluating mammography. However, we showed in this paper, the pixel SNR can produce misleading system detectability when image processing is utilized. We developed a simple, reliable and clinically applicable methodology to evaluate mammographic imaging systems using a task SNR that accounts for the imaging system performance in the presence of the patient. We used the Hotelling observer method in spatial frequency domain to calculate the task SNR of small disk test objects embedded in the breast tissue-equivalent series (BRTES) phantom for GE Senographe DS Full Field Digital Mammography (FFDM) system. The results were compared to the calculation of pixel SNR. We calculated the Hotelling observer SNR by estimating the generalized modulation transfer function (GMTF), generalized normalized noise power spectrum (GNNPS) and generalized noise equivalent quanta (GNEQ) in the presence of the breast phantom. The task SNR we calculated increased with the square root of the exposure as expected. Furthermore, we showed that the method is stable under image processing. The task SNR is a more reliable method for evaluating the performance of imaging systems especially under realistic clinical conditions where patient equivalent phantoms or image processing is used.

  17. Selective pattern enhancement processing for digital mammography, algorithms, and the visual evaluation

    NASA Astrophysics Data System (ADS)

    Yamada, Masahiko; Shimura, Kazuo; Nagata, Takefumi

    2003-05-01

    In order to enhance the micro calcifications selectively without enhancing noises, PEM (Pattern Enhancement Processing for Mammography) has been developed by utilizing not only the frequency information but also the structural information of the specified objects. PEM processing uses two structural characteristics i.e. steep edge structure and low-density isolated-point structure. The visual evaluation of PEM processing was done using two different resolution CR mammography images. The enhanced image by PEM processing was compared with the image without enhancement, and the conventional usharp-mask processed image. In the PEM processed image, an increase of noises due to enhancement was suppressed as compared with that in the conventional unsharp-mask processed image. The evaluation using CDMAM phantom showed that PEM processing improved the detection performance of a minute circular pattern. By combining PEM processing with the low and medium frequency enhancement processing, both mammary glands and micro calcifications are clearly enhanced.

  18. A New Full-Field Digital Mammography System with and without the Use of an Advanced Post-Processing Algorithm: Comparison of Image Quality and Diagnostic Performance

    PubMed Central

    Ahn, Hye Shin; Jang, Mijung; Yun, Bo La; Kim, Bohyoung; Ko, Eun Sook; Han, Boo-Kyung; Chang, Jung Min; Yi, Ann; Cho, Nariya; Moon, Woo Kyung; Choi, Hye Young

    2014-01-01

    Objective To compare new full-field digital mammography (FFDM) with and without use of an advanced post-processing algorithm to improve image quality, lesion detection, diagnostic performance, and priority rank. Materials and Methods During a 22-month period, we prospectively enrolled 100 cases of specimen FFDM mammography (Brestige®), which was performed alone or in combination with a post-processing algorithm developed by the manufacturer: group A (SMA), specimen mammography without application of "Mammogram enhancement ver. 2.0"; group B (SMB), specimen mammography with application of "Mammogram enhancement ver. 2.0". Two sets of specimen mammographies were randomly reviewed by five experienced radiologists. Image quality, lesion detection, diagnostic performance, and priority rank with regard to image preference were evaluated. Results Three aspects of image quality (overall quality, contrast, and noise) of the SMB were significantly superior to those of SMA (p < 0.05). SMB was significantly superior to SMA for visualizing calcifications (p < 0.05). Diagnostic performance, as evaluated by cancer score, was similar between SMA and SMB. SMB was preferred to SMA by four of the five reviewers. Conclusion The post-processing algorithm may improve image quality with better image preference in FFDM than without use of the software. PMID:24843234

  19. The effect of system geometry and dose on the threshold detectable calcification diameter in 2D-mammography and digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Hadjipanteli, Andria; Elangovan, Premkumar; Mackenzie, Alistair; Looney, Padraig T.; Wells, Kevin; Dance, David R.; Young, Kenneth C.

    2017-02-01

    Digital breast tomosynthesis (DBT) is under consideration to replace or to be used in combination with 2D-mammography in breast screening. The aim of this study was the comparison of the detection of microcalcification clusters by human observers in simulated breast images using 2D-mammography, narrow angle (15°/15 projections) and wide angle (50°/25 projections) DBT. The effects of the cluster height in the breast and the dose to the breast on calcification detection were also tested. Simulated images of 6 cm thick compressed breasts were produced with and without microcalcification clusters inserted, using a set of image modelling tools for 2D-mammography and DBT. Image processing and reconstruction were performed using commercial software. A series of 4-alternative forced choice (4AFC) experiments was conducted for signal detection with the microcalcification clusters as targets. Threshold detectable calcification diameter was found for each imaging modality with standard dose: 2D-mammography: 2D-mammography (165  ±  9 µm), narrow angle DBT (211  ±  11 µm) and wide angle DBT (257  ±  14 µm). Statistically significant differences were found when using different doses, but different geometries had a greater effect. No differences were found between the threshold detectable calcification diameters at different heights in the breast. Calcification clusters may have a lower detectability using DBT than 2D imaging.

  20. Establishing minimum performance standards, calibration intervals, and optimal exposure values for a whole breast digital mammography unit.

    PubMed

    Kimme-Smith, C; Lewis, C; Beifuss, M; Williams, M B; Bassett, L W

    1998-12-01

    Methods are developed to establish minimum performance standards, calibration intervals, and criteria for exposure control for a whole breast digital mammography system. A prototype phantom was designed, and an automatic method programmed, to analyze CNR, resolution, and dynamic range between CCD components in the image receptor and over time. The phantom was imaged over a 5 month period and the results are analyzed to predict future performance. White field recalibration was analyzed by subtracting white fields obtained at different intervals. Exposure effects were compared by imaging the prototype phantom at different kVp, filtration (Mo vs Rh) and mAs. Calcification detection tests showed that phantom images, obtained at 28 kVp with a Mo/Mo anode/filter and low mAs technique, often could not depict Al2O3 specks 0.24 mm in diameter, while a 28 kVp Mo/Rh, higher mAs technique usually could. Stability of the system tested suggests that monthly phantom imaging may suffice. Differences in CCD performance are greater (12%) than differences in a single CCD over time (6%). White field recalibration is needed weekly because of pixel variations in sensitivity which occur if longer intervals between recalibration occur. When mean glandular dose is matched, Rh filtration gives better phantom performance at 28 kVp than Mo filtration at 26 kVp and is recommended for clinical exposures. An aluminum step wedge shows markedly increased dynamic range when exit exposure is increased by using a higher energy spectrum beam. Phantoms for digital mammography units should cover the entire image receptor, should test intersections between components of the receptor, and should be automatically analyzed.

  1. Digital Mammography: Development of an Advanced Computer-Aided Diagnosis System for Breast Cancer Detection

    DTIC Science & Technology

    2005-05-01

    mammography system using a 1.8 X magnification geometry. A phantom -shift method equivalent to a stereo shift angle of ±3’ relative to a central axis...determine whether spiculations are present. Therefore, ste- method for phantoms and specimens in which the object is reomammography has the potential of...crimination of crossing fibrils in stereo phantom images.4’ 5’ 10 detector distance in the object-shift geometry because the Medical Physics, Vol. 32, No. 4

  2. Budget Impact Analysis of Switching to Digital Mammography in a Population-Based Breast Cancer Screening Program: A Discrete Event Simulation Model

    PubMed Central

    Comas, Mercè; Arrospide, Arantzazu; Mar, Javier; Sala, Maria; Vilaprinyó, Ester; Hernández, Cristina; Cots, Francesc; Martínez, Juan; Castells, Xavier

    2014-01-01

    Objective To assess the budgetary impact of switching from screen-film mammography to full-field digital mammography in a population-based breast cancer screening program. Methods A discrete-event simulation model was built to reproduce the breast cancer screening process (biennial mammographic screening of women aged 50 to 69 years) combined with the natural history of breast cancer. The simulation started with 100,000 women and, during a 20-year simulation horizon, new women were dynamically entered according to the aging of the Spanish population. Data on screening were obtained from Spanish breast cancer screening programs. Data on the natural history of breast cancer were based on US data adapted to our population. A budget impact analysis comparing digital with screen-film screening mammography was performed in a sample of 2,000 simulation runs. A sensitivity analysis was performed for crucial screening-related parameters. Distinct scenarios for recall and detection rates were compared. Results Statistically significant savings were found for overall costs, treatment costs and the costs of additional tests in the long term. The overall cost saving was 1,115,857€ (95%CI from 932,147 to 1,299,567) in the 10th year and 2,866,124€ (95%CI from 2,492,610 to 3,239,638) in the 20th year, representing 4.5% and 8.1% of the overall cost associated with screen-film mammography. The sensitivity analysis showed net savings in the long term. Conclusions Switching to digital mammography in a population-based breast cancer screening program saves long-term budget expense, in addition to providing technical advantages. Our results were consistent across distinct scenarios representing the different results obtained in European breast cancer screening programs. PMID:24832200

  3. Comparison of software and human observers in reading images of the CDMAM test object to assess digital mammography systems

    NASA Astrophysics Data System (ADS)

    Young, Kenneth C.; Cook, James J. H.; Oduko, Jennifer M.; Bosmans, Hilde

    2006-03-01

    European Guidelines for quality control in digital mammography specify minimum and achievable standards of image quality in terms of threshold contrast, based on readings of images of the CDMAM test object by human observers. However this is time-consuming and has large inter-observer error. To overcome these problems a software program (CDCOM) is available to automatically read CDMAM images, but the optimal method of interpreting the output is not defined. This study evaluates methods of determining threshold contrast from the program, and compares these to human readings for a variety of mammography systems. The methods considered are (A) simple thresholding (B) psychometric curve fitting (C) smoothing and interpolation and (D) smoothing and psychometric curve fitting. Each method leads to similar threshold contrasts but with different reproducibility. Method (A) had relatively poor reproducibility with a standard error in threshold contrast of 18.1 +/- 0.7%. This was reduced to 8.4% by using a contrast-detail curve fitting procedure. Method (D) had the best reproducibility with an error of 6.7%, reducing to 5.1% with curve fitting. A panel of 3 human observers had an error of 4.4% reduced to 2.9 % by curve fitting. All automatic methods led to threshold contrasts that were lower than for humans. The ratio of human to program threshold contrasts varied with detail diameter and was 1.50 +/- .04 (sem) at 0.1mm and 1.82 +/- .06 at 0.25mm for method (D). There were good correlations between the threshold contrast determined by humans and the automated methods.

  4. Experimental evaluation of the image quality and dose in digital mammography: Influence of x-ray spectrum

    NASA Astrophysics Data System (ADS)

    Tomal, A.; Perez, A. M. M. M.; Silva, M. C.; Poletti, M. E.

    2015-11-01

    In this work, we studied experimentally the influence of x-ray spectrum on the contrast-to-noise ratio (CNR) and the average glandular dose (MDG) for two digital mammography systems: Senographe 2000D (GE Medical Systems) and Lorad Selenia (Hologic), with indirect and direct detector imaging technology, respectively. CNR and MGD were determined using PMMA phantoms simulating breasts with thicknesses of 4 cm and 6 cm. All available anode/filter combinations of the systems were evaluated for a wide range of tube voltages values. Results indicated that the Rh/Rh combination provides the highest image quality with the lower mean glandular dose for the Senographe 2000D system. For the Lorad Selenia system, the W/Ag combination at 30 kV showed the best performance, in terms of dose saving and image quality improvement in relation to all tube voltage range. The comparison between the optimal x-ray spectra and those selected by the AEC mode showed that this automatic selection mechanism could be readjusted to optimize the relationship between image quality and dose.

  5. Estimating breast thickness for dual-energy subtraction in contrast-enhanced digital mammography using calibration phantoms

    NASA Astrophysics Data System (ADS)

    Lau, Kristen C.; Kwon, Young Joon; Aziz, Moez Karim; Acciavatti, Raymond J.; Maidment, Andrew D. A.

    2016-04-01

    Dual-energy contrast-enhanced digital mammography (DE CE-DM) uses an iodinated contrast agent to image the perfusion and vasculature of the breast. DE images are obtained by a weighted logarithmic subtraction of the high-energy (HE) and low-energy (LE) image pairs. We hypothesized that the optimal DE subtraction weighting factor is thickness-dependent, and developed a method for determining breast tissue composition and thickness in DE CE-DM. Phantoms were constructed using uniform blocks of 100% glandular-equivalent and 100% adipose-equivalent material. The thickness of the phantoms ranged from 3 to 8 cm, in 1 cm increments. For a given thickness, the glandular-adipose composition of the phantom was varied using different combinations of blocks. The logarithmic LE and logarithmic HE signal intensities were measured; they decrease linearly with increasing glandularity for a given thickness. The signals decrease with increasing phantom thickness and the x-ray signal decreases linearly with thickness for a given glandularity. As the thickness increases, the attenuation difference per additional glandular block decreases, indicating beam hardening. From the calibration mapping, we have demonstrated that we can predict percent glandular tissue and thickness when given two distinct signal intensities. Our results facilitate the subtraction of tissue at the boundaries of the breast, and aid in discriminating between contrast agent uptake in glandular tissue and subtraction artifacts.

  6. Mutual information-based template matching scheme for detection of breast masses: from mammography to digital breast tomosynthesis.

    PubMed

    Mazurowski, Maciej A; Lo, Joseph Y; Harrawood, Brian P; Tourassi, Georgia D

    2011-10-01

    Development of a computational decision aid for a new medical imaging modality typically is a long and complicated process. It consists of collecting data in the form of images and annotations, development of image processing and pattern recognition algorithms for analysis of the new images and finally testing of the resulting system. Since new imaging modalities are developed more rapidly than ever before, any effort for decreasing the time and cost of this development process could result in maximizing the benefit of the new imaging modality to patients by making the computer aids quickly available to radiologists that interpret the images. In this paper, we make a step in this direction and investigate the possibility of translating the knowledge about the detection problem from one imaging modality to another. Specifically, we present a computer-aided detection (CAD) system for mammographic masses that uses a mutual information-based template matching scheme with intelligently selected templates. We presented principles of template matching with mutual information for mammography before. In this paper, we present an implementation of those principles in a complete computer-aided detection system. The proposed system, through an automatic optimization process, chooses the most useful templates (mammographic regions of interest) using a large database of previously collected and annotated mammograms. Through this process, the knowledge about the task of detecting masses in mammograms is incorporated in the system. Then, we evaluate whether our system developed for screen-film mammograms can be successfully applied not only to other mammograms but also to digital breast tomosynthesis (DBT) reconstructed slices without adding any DBT cases for training. Our rationale is that since mutual information is known to be a robust inter-modality image similarity measure, it has high potential of transferring knowledge between modalities in the context of the mass detection

  7. Comparison of breast tissue measurements using magnetic resonance imaging, digital mammography and a mathematical algorithm

    NASA Astrophysics Data System (ADS)

    Lu, Lee-Jane W.; Nishino, Thomas K.; Johnson, Raleigh F.; Nayeem, Fatima; Brunder, Donald G.; Ju, Hyunsu; Leonard, Morton H., Jr.; Grady, James J.; Khamapirad, Tuenchit

    2012-11-01

    Women with mostly mammographically dense fibroglandular tissue (breast density, BD) have a four- to six-fold increased risk for breast cancer compared to women with little BD. BD is most frequently estimated from two-dimensional (2D) views of mammograms by a histogram segmentation approach (HSM) and more recently by a mathematical algorithm consisting of mammographic imaging parameters (MATH). Two non-invasive clinical magnetic resonance imaging (MRI) protocols: 3D gradient-echo (3DGRE) and short tau inversion recovery (STIR) were modified for 3D volumetric reconstruction of the breast for measuring fatty and fibroglandular tissue volumes by a Gaussian-distribution curve-fitting algorithm. Replicate breast exams (N = 2 to 7 replicates in six women) by 3DGRE and STIR were highly reproducible for all tissue-volume estimates (coefficients of variation <5%). Reliability studies compared measurements from four methods, 3DGRE, STIR, HSM, and MATH (N = 95 women) by linear regression and intra-class correlation (ICC) analyses. Rsqr, regression slopes, and ICC, respectively, were (1) 0.76-0.86, 0.8-1.1, and 0.87-0.92 for %-gland tissue, (2) 0.72-0.82, 0.64-0.96, and 0.77-0.91, for glandular volume, (3) 0.87-0.98, 0.94-1.07, and 0.89-0.99, for fat volume, and (4) 0.89-0.98, 0.94-1.00, and 0.89-0.98, for total breast volume. For all values estimated, the correlation was stronger for comparisons between the two MRI than between each MRI versus mammography, and between each MRI versus MATH data than between each MRI versus HSM data. All ICC values were >0.75 indicating that all four methods were reliable for measuring BD and that the mathematical algorithm and the two complimentary non-invasive MRI protocols could objectively and reliably estimate different types of breast tissues.

  8. Spatial recurrence analysis: A sensitive and fast detection tool in digital mammography

    SciTech Connect

    Prado, T. L.; Galuzio, P. P.; Lopes, S. R.; Viana, R. L.

    2014-03-15

    Efficient diagnostics of breast cancer requires fast digital mammographic image processing. Many breast lesions, both benign and malignant, are barely visible to the untrained eye and requires accurate and reliable methods of image processing. We propose a new method of digital mammographic image analysis that meets both needs. It uses the concept of spatial recurrence as the basis of a spatial recurrence quantification analysis, which is the spatial extension of the well-known time recurrence analysis. The recurrence-based quantifiers are able to evidence breast lesions in a way as good as the best standard image processing methods available, but with a better control over the spurious fragments in the image.

  9. The relationship between anatomic noise and volumetric breast density for digital mammography

    SciTech Connect

    Mainprize, James G.; Tyson, Albert H.; Yaffe, Martin J.

    2012-08-15

    Purpose: The appearance of parenchymal/stromal patterns in mammography have been characterized as having a Wiener power spectrum with an inverse power-law shape described by the exponential parameter, {beta}. The amount of fibroglandular tissue, which can be quantified in terms of volumetric breast density (VBD), influences the texture and appearance of the patterns formed in a mammogram. Here, a large study is performed to investigate the variations in {beta} in a clinical population and to indicate the relationship between {beta} and breast density. Methods: From a set of 2686 cranio-caudal normal screening mammograms, the parameter {beta} was extracted from log-log fits to the Wiener spectrum over the range 0.15-1 mm{sup -1}. The Wiener spectrum was calculated from regions of interest in the compression paddle contact region of the breast. An in-house computer program, Cumulus V, was used to extract the volumetric breast density and identify the compression paddle contact regions of the breast. The Wiener spectra were calculated with and without modulation transfer function (MTF) correction to determine the impact of VBD on the intrinsic anatomic noise. Results: The mean volumetric breast density was 25.5% ({+-}12.6%) over all images. The mean {beta} following a MTF correction which decreased the {beta} slightly ( Almost-Equal-To -0.08) was found to be 2.87. Varying the maximum of the spatial frequency range of the fits from 0.7 to 1.0, 1.25 or 1.5 mm{sup -1} showing small decreases in the result, although the effect of the quantum noise power component on reducing {beta} was clearly observed at 1.5 mm{sup -1}. Conclusions: The texture parameter, {beta}, was found to increase with VBD at low volumetric breast densities with an apparent leveling off at higher densities. The relationship between {beta} and VBD measured here can be used to create probabilistic models for computer simulations of detectability. As breast density is a known risk predictor for breast

  10. X-Ray Induced Formation of γ-H2AX Foci after Full-Field Digital Mammography and Digital Breast-Tomosynthesis

    PubMed Central

    Schwab, Siegfried A.; Brand, Michael; Schlude, Ina-Kristin; Wuest, Wolfgang; Meier-Meitinger, Martina; Distel, Luitpold; Schulz-Wendtland, Ruediger; Uder, Michael; Kuefner, Michael A.

    2013-01-01

    Purpose To determine in-vivo formation of x-ray induced γ-H2AX foci in systemic blood lymphocytes of patients undergoing full-field digital mammography (FFDM) and to estimate foci after FFDM and digital breast-tomosynthesis (DBT) using a biological phantom model. Materials and Methods The study complies with the Declaration of Helsinki and was performed following approval by the ethic committee of the University of Erlangen-Nuremberg. Written informed consent was obtained from every patient. For in-vivo tests, systemic blood lymphocytes were obtained from 20 patients before and after FFDM. In order to compare in-vivo post-exposure with pre-exposure foci levels, the Wilcoxon matched pairs test was used. For in-vitro experiments, isolated blood lymphocytes from healthy volunteers were irradiated at skin and glandular level of a porcine breast using FFDM and DBT. Cells were stained against the phosphorylated histone variant γ-H2AX, and foci representing distinct DNA damages were quantified. Results Median in-vivo foci level/cell was 0.086 (range 0.067–0.116) before and 0.094 (0.076–0.126) after FFDM (p = 0.0004). In the in-vitro model, the median x-ray induced foci level/cell after FFDM was 0.120 (range 0.086–0.140) at skin level and 0.035 (range 0.030–0.050) at glandular level. After DBT, the median x-ray induced foci level/cell was 0.061 (range 0.040–0.081) at skin level and 0.015 (range 0.006–0.020) at glandular level. Conclusion In patients, mammography induces a slight but significant increase of γ-H2AX foci in systemic blood lymphocytes. The introduced biological phantom model is suitable for the estimation of x-ray induced DNA damages in breast tissue in different breast imaging techniques. PMID:23936236

  11. [Follow-up of surgical biopsies in microcalcifications of the breast. Comparative analysis of patients submitted to mammography and digitalization of mammographic images].

    PubMed

    Rulli, A; Cirocchi, R; Vento, A R; Naninato, P; Zanetti, A; Carli, L

    1997-01-01

    Improvements in the techniques of preoperative needle localization of nonpalpable breast lesions that have been detected at mammography, coupled with surgical biopsy of smaller volumes of breast tissue and the use of local anesthesia have produced a more aggressive attitude toward early biopsy of lesions that are suspected of malignancy. The authors report the follow-up in 92 cases, who underwent breast biopsy for microcalcifications with no palpable lesions. In 46 women the presence of microcalcifications was evaluated through a computerized instrument which allows digitalization of the image.

  12. Surgical biopsy is still necessary for BI-RADS 4 calcifications found on digital mammography that are technically too faint for stereotactic core biopsy.

    PubMed

    Jeffries, Deborah O; Neal, Colleen H; Noroozian, Mitra; Joe, Annette I; Pinsky, Renee W; Goodsitt, Mitchell M; Helvie, Mark A

    2015-12-01

    The purpose of this study was to evaluate the outcome of faint BI-RADS 4 calcifications detected with digital mammography that were not amenable to stereotactic core biopsy due to suboptimal visualization. Following Institutional Review Board approval, a HIPAA compliant retrospective search identified 665 wire-localized surgical excisions of calcifications in 606 patients between 2007 and 2010. We included all patients that had surgical excision for initial diagnostic biopsy due to poor calcification visualization, whose current imaging was entirely digital and performed at our institution and who did not have a diagnosis of breast cancer within the prior 2 years. The final study population consisted of 20 wire-localized surgical biopsies in 19 patients performed instead of stereotactic core biopsy due to poor visibility of faint calcifications. Of the 20 biopsies, 4 (20% confidence intervals 2, 38%) were malignant, 5 (25%) showed atypia and 11 (55%) were benign. Of the malignant cases, two were invasive ductal carcinoma (2 and 1.5 mm), one was intermediate grade DCIS and one was low-grade DCIS. Malignant calcifications ranged from 3 to 12 mm. The breast density was scattered in 6/19 (32%), heterogeneously dense in 11/19 (58%) and extremely dense in 2/19 (10%). Digital mammography-detected faint calcifications that were not amenable to stereotactic biopsy due to suboptimal visualization had a risk of malignancy of 20%. While infrequent, these calcifications should continue to be considered suspicious and surgical biopsy recommended.

  13. Estimation of breast percent density in raw and processed full field digital mammography images via adaptive fuzzy c-means clustering and support vector machine segmentation

    SciTech Connect

    Keller, Brad M.; Nathan, Diane L.; Wang Yan; Zheng Yuanjie; Gee, James C.; Conant, Emily F.; Kontos, Despina

    2012-08-15

    Purpose: The amount of fibroglandular tissue content in the breast as estimated mammographically, commonly referred to as breast percent density (PD%), is one of the most significant risk factors for developing breast cancer. Approaches to quantify breast density commonly focus on either semiautomated methods or visual assessment, both of which are highly subjective. Furthermore, most studies published to date investigating computer-aided assessment of breast PD% have been performed using digitized screen-film mammograms, while digital mammography is increasingly replacing screen-film mammography in breast cancer screening protocols. Digital mammography imaging generates two types of images for analysis, raw (i.e., 'FOR PROCESSING') and vendor postprocessed (i.e., 'FOR PRESENTATION'), of which postprocessed images are commonly used in clinical practice. Development of an algorithm which effectively estimates breast PD% in both raw and postprocessed digital mammography images would be beneficial in terms of direct clinical application and retrospective analysis. Methods: This work proposes a new algorithm for fully automated quantification of breast PD% based on adaptive multiclass fuzzy c-means (FCM) clustering and support vector machine (SVM) classification, optimized for the imaging characteristics of both raw and processed digital mammography images as well as for individual patient and image characteristics. Our algorithm first delineates the breast region within the mammogram via an automated thresholding scheme to identify background air followed by a straight line Hough transform to extract the pectoral muscle region. The algorithm then applies adaptive FCM clustering based on an optimal number of clusters derived from image properties of the specific mammogram to subdivide the breast into regions of similar gray-level intensity. Finally, a SVM classifier is trained to identify which clusters within the breast tissue are likely fibroglandular, which are then

  14. Design and application of a structured phantom for detection performance comparison between breast tomosynthesis and digital mammography

    NASA Astrophysics Data System (ADS)

    Cockmartin, L.; Marshall, N. W.; Zhang, G.; Lemmens, K.; Shaheen, E.; Van Ongeval, C.; Fredenberg, E.; Dance, D. R.; Salvagnini, E.; Michielsen, K.; Bosmans, H.

    2017-02-01

    This paper introduces and applies a structured phantom with inserted target objects for the comparison of detection performance of digital breast tomosynthesis (DBT) against 2D full field digital mammography (FFDM). The phantom consists of a 48 mm thick breast-shaped polymethyl methacrylate (PMMA) container filled with water and PMMA spheres of different diameters. Three-dimensionally (3D) printed spiculated masses (diameter range: 3.8-9.7 mm) and non-spiculated masses (1.6-6.2 mm) along with microcalcifications (90-250 µm) were inserted as targets. Reproducibility of the phantom application was studied on a single system using 30 acquisitions. Next, the phantom was evaluated on five different combined FFDM & DBT systems and target detection was compared for FFDM and DBT modes. Ten phantom images in both FFDM and DBT modes were acquired on these 5 systems using automatic exposure control. Five readers evaluated target detectability. Images were read with the four-alternative forced-choice (4-AFC) paradigm, with always one segment including a target and 3 normal background segments. The percentage of correct responses (PC) was assessed based on 10 trials of each reader for each object type, size and imaging modality. Additionally, detection threshold diameters at 62.5 PC were assessed via non-linear regression fitting of the psychometric curve. The reproducibility study showed no significant differences in PC values. Evaluation of target detection in FFDM showed that microcalcification detection thresholds ranged between 110 and 118 µm and were similar compared to the detection in DBT (range of 106-158 µm). In DBT, detection of both mass types increased significantly (p  =  0.0001 and p  =  0.0002 for non-spiculated and spiculated masses respectively) compared to FFDM, achieving almost 100% detection for all spiculated mass diameters. In conclusion, a structured phantom with inserted targets was able to show evidence for detectability

  15. Design and application of a structured phantom for detection performance comparison between breast tomosynthesis and digital mammography.

    PubMed

    Cockmartin, Lesley; Marshall, Nicholas; Zhang, Guozhi; Lemmens, Kim; Shaheen, Eman; Van Ongeval, Chantal; Fredenberg, Erik; Dance, David; Salvagnini, Elena; Michielsen, Koen; Bosmans, Hilde

    2016-12-15

    This paper introduces and applies a structured phantom with target objects for the comparison of detection performance of digital breast tomosynthesis (DBT) against full field digital mammography (FFDM). The phantom consists of a 48 mm thick breast-shaped polymethyl methacrylate (PMMA) container filled with water and PMMA spheres of different diameters. Three-dimensionally (3D) printed spiculated masses (diameter range: 3.8-9.7 mm) and non-spiculated masses (1.6-6.2 mm) along with microcalcifications (90-250 µm) were inserted as targets. Reproducibility of the phantom application was studied on a single system using 30 acquisitions. Next, the phantom was evaluated on five different combined FFDM & DBT systems and target detection was compared for FFDM and DBT modes. Ten phantom images in both FFDM and DBT modes were acquired on these 5 systems using automatic exposure control (AEC). Five readers evaluated target detectability. Images were read with the four-alternative forced-choice (4-AFC) paradigm, with always one segment including a target and 3 normal background segments. The percentage of correct responses (PC) was assessed based on 10 trials of each reader for each object type, size and modality. Additionally, detection threshold diameters at 62.5 PC were assessed via non-linear regression fitting of the psychometric curve. The reproducibility study showed no significant differences in PC values. Evaluation of target detection in FFDM showed that microcalcification detection thresholds ranged between 110 and 118 µm and were similar compared to the detection in DBT (range of 106-158 µm). In DBT, detection of both mass types increased significantly (p=0.0001 and p=0.0002 for non-spiculated and spiculated masses respectively) compared to FFDM, achieving almost 100% detection for all spiculated mass diameters. In conclusion, a structured phantom with inserted targets was able to show evidence for detectability differences between FFDM and DBT modes for five

  16. Design and application of a structured phantom for detection performance comparison between breast tomosynthesis and digital mammography.

    PubMed

    Cockmartin, L; Marshall, N W; Zhang, G; Lemmens, K; Shaheen, E; Van Ongeval, C; Fredenberg, E; Dance, D R; Salvagnini, E; Michielsen, K; Bosmans, H

    2017-01-10

    This paper introduces and applies a structured phantom with inserted target objects for the comparison of detection performance of digital breast tomosynthesis (DBT) against 2D full field digital mammography (FFDM). The phantom consists of a 48 mm thick breast-shaped polymethyl methacrylate (PMMA) container filled with water and PMMA spheres of different diameters. Three-dimensionally (3D) printed spiculated masses (diameter range: 3.8-9.7 mm) and non-spiculated masses (1.6-6.2 mm) along with microcalcifications (90-250 µm) were inserted as targets. Reproducibility of the phantom application was studied on a single system using 30 acquisitions. Next, the phantom was evaluated on five different combined FFDM & DBT systems and target detection was compared for FFDM and DBT modes. Ten phantom images in both FFDM and DBT modes were acquired on these 5 systems using automatic exposure control. Five readers evaluated target detectability. Images were read with the four-alternative forced-choice (4-AFC) paradigm, with always one segment including a target and 3 normal background segments. The percentage of correct responses (PC) was assessed based on 10 trials of each reader for each object type, size and imaging modality. Additionally, detection threshold diameters at 62.5 PC were assessed via non-linear regression fitting of the psychometric curve. The reproducibility study showed no significant differences in PC values. Evaluation of target detection in FFDM showed that microcalcification detection thresholds ranged between 110 and 118 µm and were similar compared to the detection in DBT (range of 106-158 µm). In DBT, detection of both mass types increased significantly (p  =  0.0001 and p  =  0.0002 for non-spiculated and spiculated masses respectively) compared to FFDM, achieving almost 100% detection for all spiculated mass diameters. In conclusion, a structured phantom with inserted targets was able to show evidence for detectability

  17. Reference state estimation of breast computed tomography for registration with digital mammography

    NASA Astrophysics Data System (ADS)

    Samala, Ravi K.; Chan, Heang-Ping; Hadjiiski, Lubomir; Ning, Ruola; Cha, Kenny; Helvie, Mark A.

    2016-03-01

    Understanding the deformation of the breast is a fundamental aspect to lesion localization in multi-view and multimodality imaging. Finite element methods (FEMs) are commonly used to model the deformation process of the breast. In FEM, ideally a reference state of the breast with no loading conditions is available as a starting point and then appropriate imaging-modality-based loading conditions for a specific application can be applied to the breast in the reference state. We propose an iterative method to estimate the reference state configuration between a gravity loaded uncompressed breast computed tomography (BCT) volume and a compressed breast using the corresponding digital mammograms (DM) as a guide. The reference state breast model is compressed between two plates similar to mammographic imaging. A DM-like image is generated by forward ray-tracing. The iterative method applies pressure in the anterior-to-posterior direction of the breast and uses information from the DM geometry and measurements to converge on a reference state of the breast. The process of reference state estimation and breast compression was studied using BCT cases from small to large breast sizes and breast densities consisting of scattered, heterogeneous and extremely dense categories. The breasts were assumed to be composed of non-linear materials based on Mooney-Rivlin models. The effects of the material properties on the estimation process were analyzed. The Fréchet distance between the edges of the DM-like image and the DM image was used as a performance measure.

  18. Digital mammography with synchrotron radiation: characterization of a novel computed radiography system

    NASA Astrophysics Data System (ADS)

    Trivellato, S.; Vandenbroucke, D.; Arfelli, F.; Bessem, M.; Fedon, C.; Longo, R.; Tromba, G.; Taibi, A.

    2015-08-01

    Breast X-ray imaging is a continuous research field to define dedicated equipment, with specialized X-ray sources and efficient detectors to improve image quality with an equal or even lower patient dose. The Needle Imaging Plate HM5.0, produced by Agfa, has been characterized using synchrotron radiation to assess the performance of this novel imaging chain in comparison to conventional mammographic equipment. The detection performance has been initially assessed in terms of Detective Quantum Efficiency (DQE) and its computation showed that DQE curves are very close to the typical results for digital radiography systems. Image threshold contrast has been then evaluated using the CDMAM phantom. The analysis has been completed with a scoring of visible details in the radiographs of the TORMAM phantom. The characterization thus confirms that monochromaticity leads to an equal image quality with a lower glandular dose and phase-contrast effects lead to an increase in anatomical structure detectability. Finally, a preliminary evaluation of clinical images showed a clear improvement in image quality thanks to phase-contrast contribution and to detector performance.

  19. Analysis of computer-aided detection techniques and signal characteristics for clustered microcalcifications on digital mammography and digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Samala, Ravi K.; Chan, Heang-Ping; Hadjiiski, Lubomir M.; Helvie, Mark A.

    2016-10-01

    With IRB approval, digital breast tomosynthesis (DBT) images of human subjects were collected using a GE GEN2 DBT prototype system. Corresponding digital mammograms (DMs) of the same subjects were collected retrospectively from patient files. The data set contained a total of 237 views of DBT and equal number of DM views from 120 human subjects, each included 163 views with microcalcification clusters (MCs) and 74 views without MCs. The data set was separated into training and independent test sets. The pre-processing, object prescreening and segmentation, false positive reduction and clustering strategies for MC detection by three computer-aided detection (CADe) systems designed for DM, DBT, and a planar projection image generated from DBT were analyzed. Receiver operating characteristic (ROC) curves based on features extracted from microcalcifications and free-response ROC (FROC) curves based on scores from MCs were used to quantify the performance of the systems. Jackknife FROC (JAFROC) and non-parametric analysis methods were used to determine the statistical difference between the FROC curves. The difference between the CADDM and CADDBT systems when the false positive rate was estimated from cases without MCs did not reach statistical significance. The study indicates that the large search space in DBT may not be a limiting factor for CADe to achieve similar performance as that observed in DM.

  20. Computer-aided detection of masses in digital tomosynthesis mammography: Comparison of three approaches

    SciTech Connect

    Chan Heangping; Wei Jun; Zhang Yiheng; Helvie, Mark A.; Moore, Richard H.; Sahiner, Berkman; Hadjiiski, Lubomir; Kopans, Daniel B.

    2008-09-15

    The authors are developing a computer-aided detection (CAD) system for masses on digital breast tomosynthesis mammograms (DBT). Three approaches were evaluated in this study. In the first approach, mass candidate identification and feature analysis are performed in the reconstructed three-dimensional (3D) DBT volume. A mass likelihood score is estimated for each mass candidate using a linear discriminant analysis (LDA) classifier. Mass detection is determined by a decision threshold applied to the mass likelihood score. A free response receiver operating characteristic (FROC) curve that describes the detection sensitivity as a function of the number of false positives (FPs) per breast is generated by varying the decision threshold over a range. In the second approach, prescreening of mass candidate and feature analysis are first performed on the individual two-dimensional (2D) projection view (PV) images. A mass likelihood score is estimated for each mass candidate using an LDA classifier trained for the 2D features. The mass likelihood images derived from the PVs are backprojected to the breast volume to estimate the 3D spatial distribution of the mass likelihood scores. The FROC curve for mass detection can again be generated by varying the decision threshold on the 3D mass likelihood scores merged by backprojection. In the third approach, the mass likelihood scores estimated by the 3D and 2D approaches, described above, at the corresponding 3D location are combined and evaluated using FROC analysis. A data set of 100 DBT cases acquired with a GE prototype system at the Breast Imaging Laboratory in the Massachusetts General Hospital was used for comparison of the three approaches. The LDA classifiers with stepwise feature selection were designed with leave-one-case-out resampling. In FROC analysis, the CAD system for detection in the DBT volume alone achieved test sensitivities of 80% and 90% at average FP rates of 1.94 and 3.40 per breast, respectively. With the

  1. A similarity learning approach to content-based image retrieval: application to digital mammography.

    PubMed

    El-Naqa, Issam; Yang, Yongyi; Galatsanos, Nikolas P; Nishikawa, Robert M; Wernick, Miles N

    2004-10-01

    In this paper, we describe an approach to content-based retrieval of medical images from a database, and provide a preliminary demonstration of our approach as applied to retrieval of digital mammograms. Content-based image retrieval (CBIR) refers to the retrieval of images from a database using information derived from the images themselves, rather than solely from accompanying text indices. In the medical-imaging context, the ultimate aim of CBIR is to provide radiologists with a diagnostic aid in the form of a display of relevant past cases, along with proven pathology and other suitable information. CBIR may also be useful as a training tool for medical students and residents. The goal of information retrieval is to recall from a database information that is relevant to the user's query. The most challenging aspect of CBIR is the definition of relevance (similarity), which is used to guide the retrieval machine. In this paper, we pursue a new approach, in which similarity is learned from training examples provided by human observers. Specifically, we explore the use of neural networks and support vector machines to predict the user's notion of similarity. Within this framework we propose using a hierarchal learning approach, which consists of a cascade of a binary classifier and a regression module to optimize retrieval effectiveness and efficiency. We also explore how to incorporate online human interaction to achieve relevance feedback in this learning framework. Our experiments are based on a database consisting of 76 mammograms, all of which contain clustered microcalcifications (MCs). Our goal is to retrieve mammogram images containing similar MC clusters to that in a query. The performance of the retrieval system is evaluated using precision-recall curves computed using a cross-validation procedure. Our experimental results demonstrate that: 1) the learning framework can accurately predict the perceptual similarity reported by human observers, thereby

  2. Detective quantum efficiency measured as a function of energy for two full-field digital mammography systems.

    PubMed

    Marshall, N W

    2009-05-07

    This paper presents detective quantum efficiency (DQE) data measured for a range of x-ray beam qualities for two full-field digital mammography (FFDM) systems: a caesium iodide (CsI) detector-based unit and a system designed around an amorphous selenium (a-Se) x-ray detector. Four beam qualities were studied for each system, covering mean energies from 17.8 keV to 23.4 keV for the CsI system and 17.8 keV to 24.7 keV for the a-Se unit. These were set using 2, 4, 6 and 7 cm polymethylmethacralate (PMMA) and typical tube voltage and target/filter combinations selected by the automatic exposure control (AEC) program used clinically on these systems. Normalized noise power spectra (NNPS) were calculated from flood images acquired at these beam qualities for a target detector air kerma of 100 microGy. Modulation transfer function (MTF) data were acquired at 28 kV and Mo/Mo target/filter setting. The DQE was then calculated from the MTF and NNPS results. For comparison, the quantum detective efficiency (QDE) and energy absorption efficiency (EAE) were calculated from tabulated narrow beam spectral data. With regard to detector response, some energy dependence was noted for pixel value plotted against air kerma at the detector. This amounted to a change in the gradient of the detector response of approximately 15% and 30% per keV for the CsI- and a-Se-based systems, respectively. For the DQE results, a reduction in DQE(0) of 22% was found for the CsI-based unit as beam quality changed from 25 kV Mo/Mo and 2 cm PMMA to 32 kV Rh/Rh and 7 cm PMMA. For the a-Se system, a change in beam quality from 25 kV Mo/Mo and 2 cm PMMA to 34 kV Mo/Rh and 7 cm PMMA led to a reduction in DQE(0) of 8%. Comparing measured data with simple calculations, a reduction in x-ray quantum detection efficiency of 27% was expected for the CsI-based system, while a reduction of 11% was predicted for the a-Se system.

  3. Detective quantum efficiency measured as a function of energy for two full-field digital mammography systems

    NASA Astrophysics Data System (ADS)

    Marshall, N. W.

    2009-05-01

    This paper presents detective quantum efficiency (DQE) data measured for a range of x-ray beam qualities for two full-field digital mammography (FFDM) systems: a caesium iodide (CsI) detector-based unit and a system designed around an amorphous selenium (a-Se) x-ray detector. Four beam qualities were studied for each system, covering mean energies from 17.8 keV to 23.4 keV for the CsI system and 17.8 keV to 24.7 keV for the a-Se unit. These were set using 2, 4, 6 and 7 cm polymethylmethacralate (PMMA) and typical tube voltage and target/filter combinations selected by the automatic exposure control (AEC) program used clinically on these systems. Normalized noise power spectra (NNPS) were calculated from flood images acquired at these beam qualities for a target detector air kerma of 100 µGy. Modulation transfer function (MTF) data were acquired at 28 kV and Mo/Mo target/filter setting. The DQE was then calculated from the MTF and NNPS results. For comparison, the quantum detective efficiency (QDE) and energy absorption efficiency (EAE) were calculated from tabulated narrow beam spectral data. With regard to detector response, some energy dependence was noted for pixel value plotted against air kerma at the detector. This amounted to a change in the gradient of the detector response of approximately 15% and 30% per keV for the CsI- and a-Se-based systems, respectively. For the DQE results, a reduction in DQE(0) of 22% was found for the CsI-based unit as beam quality changed from 25 kV Mo/Mo and 2 cm PMMA to 32 kV Rh/Rh and 7 cm PMMA. For the a-Se system, a change in beam quality from 25 kV Mo/Mo and 2 cm PMMA to 34 kV Mo/Rh and 7 cm PMMA led to a reduction in DQE(0) of 8%. Comparing measured data with simple calculations, a reduction in x-ray quantum detection efficiency of 27% was expected for the CsI-based system, while a reduction of 11% was predicted for the a-Se system.

  4. Determination of Tube Output (kVp) and Exposure Mode for Breast Phantom of Various Thicknesses/Glandularity for Digital Mammography

    PubMed Central

    IZDIHAR, Kamal; KANAGA, Kumari Chelliah; KRISHNAPILLAI, Vijayalakshimi; SULAIMAN, Tamanang

    2015-01-01

    Background: Optimisation of average glandular dose (AGD) for two-dimensional (2D) mammography is important, as imaging using ionizing radiation has the probability to induce cancer resulting from stochastic effects. This study aims to observe the effects of kVp, anode/filter material, and exposure mode on the dose and image quality of 2D mammography. Methods: This experimental study was conducted using full-field digital mammography. The entrance surface air kerma was determined using thermoluminescent dosimeter (TLD) 100H and ionization chamber (IC) on three types of Computerized Imaging Reference System (CIRS) phantom with 50/50, 30/70, and 20/80 breast glandularity, respectively, in the auto-time mode and auto-filter mode. The Euref protocol was used to calculate the AGD while the image quality was evaluated using contrast-to-noise ratio (CNR), figure of merit (FOM), and image quality figure (IQF). Results: It is shown that AGD values in the auto-time mode did not decrease significantly with the increasing tube voltage of the silver filter (r = −0.187, P > 0.05) and rhodium filter (r = −0.131, P > 0.05) for all the phantoms. The general linear model showed that AGD for all phantoms had a significant effect between different exposure factors [F (6,12.3) = 4.48 and mode of exposure F (1,86) = 4.17, P < 0.05, respectively] but there is no significant difference between the different anode/filter combination [F (1,4) = 0.571]. Conclusion: In summary, the 28, 29, and 31 kVp are the optimum kVp for 50%, 30%, and 20% breast glandularity, respectively. Besides the auto-filter mode is suitable for 50%, 30%, and 20% breast glandularity because it is automatic, faster, and may avoid error done by the operator. PMID:25892949

  5. Towards standardization of x-ray beam filters in digital mammography and digital breast tomosynthesis: Monte Carlo simulations and analytical modelling

    NASA Astrophysics Data System (ADS)

    Shrestha, Suman; Vedantham, Srinivasan; Karellas, Andrew

    2017-03-01

    In digital breast tomosynthesis and digital mammography, the x-ray beam filter material and thickness vary between systems. Replacing K-edge filters with Al was investigated with the intent to reduce exposure duration and to simplify system design. Tungsten target x-ray spectra were simulated with K-edge filters (50 µm Rh; 50 µm Ag) and Al filters of varying thickness. Monte Carlo simulations were conducted to quantify the x-ray scatter from various filters alone, scatter-to-primary ratio (SPR) with compressed breasts, and to determine the radiation dose to the breast. These data were used to analytically compute the signal-difference-to-noise ratio (SDNR) at unit (1 mGy) mean glandular dose (MGD) for W/Rh and W/Ag spectra. At SDNR matched between K-edge and Al filtered spectra, the reductions in exposure duration and MGD were quantified for three strategies: (i) fixed Al thickness and matched tube potential in kilovolts (kV); (ii) fixed Al thickness and varying the kV to match the half-value layer (HVL) between Al and K-edge filtered spectra; and, (iii) matched kV and varying the Al thickness to match the HVL between Al and K-edge filtered spectra. Monte Carlo simulations indicate that the SPR with and without the breast were not different between Al and K-edge filters. Modelling for fixed Al thickness (700 µm) and kV matched to K-edge filtered spectra, identical SDNR was achieved with 37–57% reduction in exposure duration and with 2–20% reduction in MGD, depending on breast thickness. Modelling for fixed Al thickness (700 µm) and HVL matched by increasing the kV over (0,4) range, identical SDNR was achieved with 62–65% decrease in exposure duration and with 2–24% reduction in MGD, depending on breast thickness. For kV and HVL matched to K-edge filtered spectra by varying Al filter thickness over (700, 880) µm range, identical SDNR was achieved with 23–56% reduction in exposure duration and 2–20% reduction in MGD, depending on breast thickness

  6. Breast Imaging Reporting and Data System (BI-RADS) breast composition descriptors: Automated measurement development for full field digital mammography

    SciTech Connect

    Fowler, E. E.; Sellers, T. A.; Lu, B.; Heine, J. J.

    2013-11-15

    Purpose: The Breast Imaging Reporting and Data System (BI-RADS) breast composition descriptors are used for standardized mammographic reporting and are assessed visually. This reporting is clinically relevant because breast composition can impact mammographic sensitivity and is a breast cancer risk factor. New techniques are presented and evaluated for generating automated BI-RADS breast composition descriptors using both raw and calibrated full field digital mammography (FFDM) image data.Methods: A matched case-control dataset with FFDM images was used to develop three automated measures for the BI-RADS breast composition descriptors. Histograms of each calibrated mammogram in the percent glandular (pg) representation were processed to create the new BR{sub pg} measure. Two previously validated measures of breast density derived from calibrated and raw mammograms were converted to the new BR{sub vc} and BR{sub vr} measures, respectively. These three measures were compared with the radiologist-reported BI-RADS compositions assessments from the patient records. The authors used two optimization strategies with differential evolution to create these measures: method-1 used breast cancer status; and method-2 matched the reported BI-RADS descriptors. Weighted kappa (κ) analysis was used to assess the agreement between the new measures and the reported measures. Each measure's association with breast cancer was evaluated with odds ratios (ORs) adjusted for body mass index, breast area, and menopausal status. ORs were estimated as per unit increase with 95% confidence intervals.Results: The three BI-RADS measures generated by method-1 had κ between 0.25–0.34. These measures were significantly associated with breast cancer status in the adjusted models: (a) OR = 1.87 (1.34, 2.59) for BR{sub pg}; (b) OR = 1.93 (1.36, 2.74) for BR{sub vc}; and (c) OR = 1.37 (1.05, 1.80) for BR{sub vr}. The measures generated by method-2 had κ between 0.42–0.45. Two of these measures

  7. An Evaluation of Stereoscopic Digital Mammography for Earlier Detection of Breast Cancer and Reduced Rate of Recall

    DTIC Science & Technology

    2008-08-01

    in the DICOM header. We decided on a new, desired grayscale mean that we wanted all images to share, and used the difference between each stored...software to anonymize the DICOM file headers of a given case’s images, ZIP the images into a single file, and then transmit the anonymized case over the...mammography 31 phantoms (7). While this finding would have to be confirmed in a clinical setting, we expect that the effect of stereo with half-dose image

  8. Estimation of mean glandular dose for contrast enhanced digital mammography: factors for use with the UK, European and IAEA breast dosimetry protocols.

    PubMed

    Dance, D R; Young, K C

    2014-05-07

    The UK, European and IAEA protocols for breast dosimetry in mammography use tabulations of conversion factors, which relate measurements of incident air kerma to the mean glandular dose to the breast. To supplement the existing tabulations, a Monte Carlo computer program has been used to calculate conversion factors for the high-energy spectra used for contrast enhanced digital mammography. The calculations were made for the x-ray spectra from a tungsten target (tube voltage range 40-50 kV) filtered by 0.28, 0.30 and 0.32 mm of copper, and from molybdenum and rhodium targets (tube voltage range 40-49 kV), each filtered by 0.30 mm of copper. The g-factors for all of these spectra were plotted for each breast thickness as a function of half value layer (HVL) and were found to lie on smooth curves within 0.3%. These reflect the fact that the characteristic x-rays present in the spectra from molybdenum and rhodium are heavily filtered and all the spectra are essentially Bremsstrahlung. As a consequence, the s-factor previously used in the dosimetry protocols to adjust for different target/filter combinations can be taken as unity for all of the spectra considered. Tables of g-factors and c-factors are provided for breast thicknesses in the range 20-110 mm and HVLs in the range 2.4-3.6 mm of aluminium. The tables of c-factors are given for breast glandularities in the range 0.1%-100% and for typical glandularities for women in the age bands 40-49 and 50-64 attending the UK national breast screening programme.

  9. SU-E-I-45: Feasibility for Using Iodine Quantification to Assist Diagnosis in Dual Energy Contrast-Enhanced Digital Mammography

    SciTech Connect

    Hwang, Y; Lin, Y; Tsai, C; Cheung, Y

    2015-06-15

    Purpose: The objective of this study is to develop quantitative calibration between image quality indexes and iodine concentration with dual-energy (DE) contrast-enhanced digital mammography (CEDM) techniques and further serve as the assistance for diagnosis. Methods: Custom-made acrylic phantom with dimensions of 24×30 cm{sup 2} simulated breast thickness from 2 to 6 cm was used in the calibration. The phantom contained matrix of four times four holes of 3 mm deep with a diameter of 15 mm for filling contrast agent with area density ranged from 0.1 to 10 mg/cm{sup 2}. All the image acquisitions were performed on a full-field digital mammography system (Senographe Essential, GE) with dual energy acquisitions. Mean pixel value (MPV), and contrast-to-noise ratio (CNR) were used for evaluating the relationship between image quality indexes and iodine concentration. Iodine map and CNR map could further be constructed with these calibration curves applied pixel by pixel utilized MATLAB software. Minimum iodine concentration could also be calculated with the visibility threshold of CNR=5 according the Rose model. Results: When evaluating the DE subtraction images, MPV increased linearly as the iodine concentration increased with all the phantom thickness surveyed (R{sup 2} between 0.989 and 0.992). Lesions with increased iodine uptake could thus be enhanced in the color-encoded iodine maps, and the mean iodine concentration could be obtained through the ROI measurements. As for investigating CNR performance, linear relationships were also shown between the iodine concentration and CNR (R{sup 2} between 0.983 and 0.990). Minimum iodine area density of 1.45, 1.73, 1.80, 1.73 and 1.72 mg/cm{sup 2} for phantom thickness of 2, 3, 4, 5, 6 cm were calculated based on Rose’s visualization criteria. Conclusion: Quantitative calibration between image quality indexes and iodine concentrations may further serving as the assistance for analyzing contrast enhancement for patient

  10. Can the evaluation of a simple test object be used to predict the performance of a contrast-detail analysis in digital mammography?

    NASA Astrophysics Data System (ADS)

    Bosmans, H.; Lemmens, K.; Jacobs, J.; Vandenbroucke, D.; Zanca, F.; Michielsen, K.; Verbrugge, B.; Smans, K.; Marchal, G.

    2009-02-01

    The purpose was to find the correlation between a Figure of Merit (FoM) calculated from a new (simple) test object for Quality Control in digital mammography and CDMAM threshold thicknesses. The FoM included the signal difference to noise ratio, modulation transfer function of the complete system (including scatter and grid) and normalized noise power spectrum. The pre-programmed exposure settings for clinical work were used, as was done for the CDMAM acquisitions. The FoM is calculated from 2 images only (an image from the QC test object and an image of a corresponding homogeneous plate imaged with the same exposure settings). This FoM was evaluated in frequencies that match with the diameters of the gold disks in the CDMAM phantom. Computerized CDMAM analysis uses 16 images per system. The software program "cdcom" (www.euref.org) was used for the 4-AFC experiment. All matrices were averaged, smoothed with a Gaussian filter and psychometric curves were fitted through the correctly detected fractions to obtain the threshold thickness with a detectability of 62.5% for all diameters. Images have been acquired on 10 different systems (2 computed radiography (CR) systems, 6 direct radiology (DR) systems and 2 photon counting systems). The reproducibility of the QC metrics from images of the new phantom was assessed. The standard error on the mean of the FoM was for the highest frequency 8.1% for a CR system and 5.6% for a DR system. The main component in this error is due to the NNPS and the limited number of independent pixels used in this analysis. Parameters calculated from both phantoms are sensitive to variation in mean glandular dose levels. Present results show a weak correlation (R2=0.60) between the FoM at 5lp/mm and CDMAM threshold values for the 0.1mm objects when all system data are pooled. If evaluated for separate systems, the correlation holds promise for automated, periodic performance evaluations of digital mammography systems with the simplified

  11. Dual-energy digital mammography: calibration and inverse-mapping techniques to estimate calcification thickness and glandular-tissue ratio.

    PubMed

    Kappadath, S Cheenu; Shaw, Chris C

    2003-06-01

    Breast cancer may manifest as microcalcifications in x-ray mammography. Small microcalcifications, essential to the early detection of breast cancer, are often obscured by overlapping tissue structures. Dual-energy imaging, where separate low- and high-energy images are acquired and synthesized to cancel the tissue structures, may improve the ability to detect and visualize microcalcifications. Transmission measurements at two different kVp values were made on breast-tissue-equivalent materials under narrow-beam geometry using an indirect flat-panel mammographic imager. The imaging scenario consisted of variable aluminum thickness (to simulate calcifications) and variable glandular ratio (defined as the ratio of the glandular-tissue thickness to the total tissue thickness) for a fixed total tissue thickness--the clinical situation of microcalcification imaging with varying tissue composition under breast compression. The coefficients of the inverse-mapping functions used to determine material composition from dual-energy measurements were calculated by a least-squares analysis. The linear function poorly modeled both the aluminum thickness and the glandular ratio. The inverse-mapping functions were found to vary as analytic functions of second (conic) or third (cubic) order. By comparing the model predictions with the calibration values, the root-mean-square residuals for both the cubic and the conic functions were approximately 50 microm for the aluminum thickness and approximately 0.05 for the glandular ratio.

  12. Image quality evaluation of direct-conversion digital mammography system with new dual a-Se layer detector

    NASA Astrophysics Data System (ADS)

    Kuwabara, Takao; Iwasaki, Nobuyuki; Sendai, Tomonari; Furue, Ryosuke; Agano, Toshitaka

    2009-02-01

    To increase the detection performance of breast cancers in mammograms, we need to improve shape delineation of micro calcifications and tumors. We accomplished this by developing a direct-conversion mammography system with an optical reading method and a new dual a-Se layer detector. The system achieved both small pixel size (50 micrometer) and a high Detective Quantum Efficiency (DQE) realized by 100 % of fill factor and noise reduction. We evaluated image quality performance and determined the best exposure conditions. We measured DQE and Modulation Transfer Function(MTF) according to the IEC62220-1-2. High DQE was maintained at a low radiation dosage, indicating that the optical reading method accompanies low noises. Response of MTF was maintained at up to the Nyquist frequency of 10 cyc/mm, which corresponds to 50 micrometer pixel size. To determine the best exposure conditions, we measured Contrast to Noise Ratio (CNR) and visually evaluated images of a resected breast under conditions of MoMo, MoRh, and WRh. There were occasional disagreements between the exposure conditions for achieving the maximum CNR and those for the best image graded by the visual evaluation. This was probably because CNR measurement does not measure effects of scattered X-ray. The images verified the improvement in detection and delineation performance of micro calcifications and tumors.

  13. Composite x-ray image assembly for large-field digital mammography with one- and two-dimensional positioning of a focal plane array

    NASA Technical Reports Server (NTRS)

    Halama, G.; McAdoo, J.; Liu, H.

    1998-01-01

    To demonstrate the feasibility of a novel large-field digital mammography technique, a 1024 x 1024 pixel Loral charge-coupled device (CCD) focal plane array (FPA) was positioned in a mammographic field with one- and two-dimensional scan sequences to obtain 950 x 1800 pixel and 3600 x 3600 pixel composite images, respectively. These experiments verify that precise positioning of FPAs produced seamless composites and that the CCD mosaic concept has potential for high-resolution, large-field imaging. The proposed CCD mosaic concept resembles a checkerboard pattern with spacing left between the CCDs for the driver and readout electronics. To obtain a complete x-ray image, the mosaic must be repositioned four times, with an x-ray exposure at each position. To reduce the patient dose, a lead shield with appropriately patterned holes is placed between the x-ray source and the patient. The high-precision motorized translation stages and the fiber-coupled-scintillating-screen-CCD sensor assembly were placed in the position usually occupied by the film cassette. Because of the high mechanical precision, seamless composites were constructed from the subimages. This paper discusses the positioning, image alignment procedure, and composite image results. The paper only addresses the formation of a seamless composite image from subimages and will not consider the effects of the lead shield, multiple CCDs, or the speed of motion.

  14. Dose optimization for dual-energy contrast-enhanced digital mammography based on an energy-resolved photon-counting detector: A Monte Carlo simulation study

    NASA Astrophysics Data System (ADS)

    Lee, Youngjin; Lee, Seungwan; Kang, Sooncheol; Eom, Jisoo

    2017-03-01

    Dual-energy contrast-enhanced digital mammography (CEDM) has been used to decompose breast images and improve diagnostic accuracy for tumor detection. However, this technique causes an increase of radiation dose and an inaccuracy in material decomposition due to the limitations of conventional X-ray detectors. In this study, we simulated the dual-energy CEDM with an energy-resolved photon-counting detector (ERPCD) for reducing radiation dose and improving the quantitative accuracy of material decomposition images. The ERPCD-based dual-energy CEDM was compared to the conventional dual-energy CEDM in terms of radiation dose and quantitative accuracy. The correlation between radiation dose and image quality was also evaluated for optimizing the ERPCD-based dual-energy CEDM technique. The results showed that the material decomposition errors of the ERPCD-based dual-energy CEDM were 0.56-0.67 times lower than those of the conventional dual-energy CEDM. The imaging performance of the proposed technique was optimized at the radiation dose of 1.09 mGy, which is a half of the MGD for a single view mammogram. It can be concluded that the ERPCD-based dual-energy CEDM with an optimal exposure level is able to improve the quality of material decomposition images as well as reduce radiation dose.

  15. Dose reduction and its influence on diagnostic accuracy and radiation risk in digital mammography: an observer performance study using an anthropomorphic breast phantom

    PubMed Central

    Svahn, Tony; Hemdal, Bengt; Ruschin, Mark; Chakraborty, Dev P; Andersson, Ingvar; Tingberg, Anders; Mattsson, Sören

    2008-01-01

    This study aimed to investigate the effect of dose reduction on diagnostic accuracy and radiation risk in digital mammography. Simulated masses and microcalcifications were positioned in an anthropomorphic breast phantom. Thirty digital images, 14 with lesions, 16 without, were acquired of the phantom using a Mammomat Novation (Siemens, Erlangen, Germany) at each of three dose levels. These corresponded to 100%, 50% and 30% of the normally used average glandular dose (AGD; 1.3 mGy for a standard breast). Eight observers interpreted the 90 unprocessed images in a free-response study and the data was analyzed with the jackknife free-response receiver operating characteristic (JAFROC) method. Observer performance was assessed using the JAFROC figure of merit (FOM). The benefit of radiation risk reduction was estimated based on several risk models. There was no statistically significant difference in performance, as described by the FOM, between the 100% and the 50% dose levels. However, the FOMs for both the 100% and the 50% dose were significantly different from the corresponding quantity for the 30% dose level (F-statistic = 4.95, p-value = 0.01). A dose reduction of 50% would result in 3-9 fewer breast cancer fatalities per 100,000 women undergoing annual screening from the age of 40 to 49 years. The results of the study indicate a possibility of reducing the dose to the breast to half of the dose level currently used. This has to be confirmed in clinical studies and possible differences depending on lesion type should be further examined. PMID:17704316

  16. FDA Certified Mammography Facilities

    MedlinePlus

    ... Products Radiation-Emitting Products Home Radiation-Emitting Products Mammography Quality Standards Act and Program Consumer Information (MQSA) ... it Email Print This list of FDA Certified Mammography Facilities is updated weekly. If you click on ...

  17. An Evaluation of Stereoscopic Digital Mammography for Earlier Detection of Breast Cancer and Reduced Rate of Recall

    DTIC Science & Technology

    2007-08-01

    the patient is immobile. For ophthalmic photography a fundus camera30 is used and the stereo pair of images , either film- based or digital, is...standard” technique for diagnosis. The ETDRS standard protocol calls for acquisition of seven stereo image pairs for each retina using a fundus ...September 23, 2004. 41 L A Yanuzzi et al, “Ophthalmic Fundus imaging : Today and beyond,” Am J Ophthal 137, 511 (2004). 42 A Yaron, M Shecterman, and N

  18. Automatic Estimation of Volumetric Breast Density Using Artificial Neural Network-Based Calibration of Full-Field Digital Mammography: Feasibility on Japanese Women With and Without Breast Cancer.

    PubMed

    Wang, Jeff; Kato, Fumi; Yamashita, Hiroko; Baba, Motoi; Cui, Yi; Li, Ruijiang; Oyama-Manabe, Noriko; Shirato, Hiroki

    2016-11-10

    Breast cancer is the most common invasive cancer among women and its incidence is increasing. Risk assessment is valuable and recent methods are incorporating novel biomarkers such as mammographic density. Artificial neural networks (ANN) are adaptive algorithms capable of performing pattern-to-pattern learning and are well suited for medical applications. They are potentially useful for calibrating full-field digital mammography (FFDM) for quantitative analysis. This study uses ANN modeling to estimate volumetric breast density (VBD) from FFDM on Japanese women with and without breast cancer. ANN calibration of VBD was performed using phantom data for one FFDM system. Mammograms of 46 Japanese women diagnosed with invasive carcinoma and 53 with negative findings were analyzed using ANN models learned. ANN-estimated VBD was validated against phantom data, compared intra-patient, with qualitative composition scoring, with MRI VBD, and inter-patient with classical risk factors of breast cancer as well as cancer status. Phantom validations reached an R (2) of 0.993. Intra-patient validations ranged from R (2) of 0.789 with VBD to 0.908 with breast volume. ANN VBD agreed well with BI-RADS scoring and MRI VBD with R (2) ranging from 0.665 with VBD to 0.852 with breast volume. VBD was significantly higher in women with cancer. Associations with age, BMI, menopause, and cancer status previously reported were also confirmed. ANN modeling appears to produce reasonable measures of mammographic density validated with phantoms, with existing measures of breast density, and with classical biomarkers of breast cancer. FFDM VBD is significantly higher in Japanese women with cancer.

  19. A New Flat-Panel Digital Mammography Detector with Avalanche Photoconductor and High-Resolution Field Emitter Readout

    DTIC Science & Technology

    2005-06-01

    electric field Ese as opposed to the fixed high conversion gain of HgI 2 or PbI2. One of 4 the practical problems of having a fixed high gain is that the...Nylen, K. Shah, L. Melekhov and H. Hermon, "Comparison of PbI2 and HgI 2 for direct detection active matrix x-ray image sensors", J. Appl. Phys. 91...a-Se and HgI 2", Appl. Phys. Lett. 80, 1664-1666 (2002) 23 14 N. Matsuura, Wei Zhao, Z. Huang and J. A. Rowlands, "Digital radiology using active

  20. Small fields: Nonequilibrium radiation dosimetry

    SciTech Connect

    Das, Indra J.; Ding, George X.; Ahnesjoe, Anders

    2008-01-15

    Advances in radiation treatment with beamlet-based intensity modulation, image-guided radiation therapy, and stereotactic radiosurgery (including specialized equipments like CyberKnife, Gamma Knife, tomotherapy, and high-resolution multileaf collimating systems) have resulted in the use of reduced treatment fields to a subcentimeter scale. Compared to the traditional radiotherapy with fields {>=}4x4 cm{sup 2}, this can result in significant uncertainty in the accuracy of clinical dosimetry. The dosimetry of small fields is challenging due to nonequilibrium conditions created as a consequence of the secondary electron track lengths and the source size projected through the collimating system that are comparable to the treatment field size. It is further complicated by the prolonged electron tracks in the presence of low-density inhomogeneities. Also, radiation detectors introduced into such fields usually perturb the level of disequilibrium. Hence, the dosimetric accuracy previously achieved for standard radiotherapy applications is at risk for both absolute and relative dose determination. This article summarizes the present knowledge and gives an insight into the future procedures to handle the nonequilibrium radiation dosimetry problems. It is anticipated that new miniature detectors with controlled perturbations and corrections will be available to meet the demand for accurate measurements. It is also expected that the Monte Carlo techniques will increasingly be used in assessing the accuracy, verification, and calculation of dose, and will aid perturbation calculations of detectors used in small and highly conformal radiation beams.

  1. Full Field Digital Mammography (FFDM) versus CMOS Technology, Specimen Radiography System (SRS) and Tomosynthesis (DBT) - Which System Can Optimise Surgical Therapy?

    PubMed

    Schulz-Wendtland, R; Dilbat, G; Bani, M; Fasching, P A; Heusinger, K; Lux, M P; Loehberg, C R; Brehm, B; Hammon, M; Saake, M; Dankerl, P; Jud, S M; Rauh, C; Bayer, C M; Beckmann, M W; Uder, M; Meier-Meitinger, M

    2013-05-01

    Aim: This prospective clinical study aimed to evaluate whether it would be possible to reduce the rate of re-excisions using CMOS technology, a specimen radiography system (SRS) or digital breast tomosynthesis (DBT) compared to a conventional full field digital mammography (FFDM) system. Material and Method: Between 12/2012 and 2/2013 50 patients were diagnosed with invasive breast cancer (BI-RADS™ 5). After histological verification, all patients underwent breast-conserving therapy with intraoperative imaging using 4 different systems and differing magnifications: 1. Inspiration™ (Siemens, Erlangen, Germany), amorphous selenium, tungsten source, focus 0.1 mm, resolution 85 µm pixel pitch, 8 lp/mm; 2. BioVision™ (Bioptics, Tucson, AZ, USA), CMOS technology, photodiode array, flat panel, tungsten source, focus 0.05, resolution 50 µm pixel pitch, 12 lp/mm; 3. the Trident™ specimen radiography system (SRS) (Hologic, Bedford, MA, USA), amorphous selenium, tungsten source, focus 0.05, resolution 70 µm pixel pitch, 7.1 lp/mm; 4. tomosynthesis (Siemens, Erlangen, Germany), amorphous selenium, tungsten source, focus 0.1 mm, resolution 85 µm pixel pitch, 8 lp/mm, angular range 50 degrees, 25 projections, scan time > 20 s, geometry: uniform scanning, reconstruction: filtered back projection. The 600 radiographs were prospectively shown to 3 radiologists. Results: Of the 50 patients with histologically proven breast cancer (BI-RADS™ 6), 39 patients required no further surgical therapy (re-excision) after breast-conserving surgery. A retrospective analysis (n = 11) showed a significant (p < 0.05) increase of sensitivity with the BioVision™, the Trident™ and tomosynthesis compared to the Inspiration™ at a magnification of 1.0 : 2.0 or 1.0 : 1.0 (tomosynthesis) (2.6, 3.3 or 3.6 %), i.e. re-excision would not have been necessary in 2, 3 or 4 patients, respectively, compared to findings obtained with a standard

  2. Barriers to screening mammography.

    PubMed

    Sarma, Elizabeth A

    2015-01-01

    Breast cancer (BRCA) is the second most commonly diagnosed cancer among women in the USA, and mammography is an effective means for the early detection of BRCA. Identifying the barriers to screening mammography can inform research, policy and practice aiming to increase mammography adherence. A literature review was conducted to determine common barriers to screening mammography adherence. PsycINFO and PubMed databases were searched to identify studies published between 2000 and 2012 that examined barriers associated with reduced mammography adherence. Three thematic groups of barriers, based on social ecology, were identified from the literature: healthcare system-level, social and individual-level barriers. Researchers must consider screening behaviour in context and, therefore, should simultaneously consider each level of barriers when attempting to understand screening behaviour and create interventions to increase mammography adherence.

  3. Pilot Study on the Detection of Simulated Lesions Using a 2D and 3D Digital Full-Field Mammography System with a Newly Developed High Resolution Detector Based on Two Shifts of a-Se.

    PubMed

    Schulz-Wendtland, R; Bani, M; Lux, M P; Schwab, S; Loehberg, C R; Jud, S M; Rauh, C; Bayer, C M; Beckmann, M W; Uder, M; Fasching, P A; Adamietz, B; Meier-Meitinger, M

    2012-05-01

    Purpose: Experimental study of a new system for digital 2D and 3D full-field mammography (FFDM) using a high resolution detector based on two shifts of a-Se. Material and Methods: Images were acquired using the new FFDM system Amulet® (FujiFilm, Tokio, Japan), an a-Se detector (receptor 24 × 30 cm(2), pixel size 50 µm, memory depth 12 bit, spatial resolution 10 lp/mm, DQE > 0.50). Integrated in the detector is a new method for data transfer, based on optical switch technology. The object of investigation was the Wisconsin Mammographic Random Phantom, Model 152A (Radiation Measurement Inc., Middleton, WI, USA) and the same parameters and exposure data (Tungsten, 100 mAs, 30 kV) were consistently used. We acquired 3 different pairs of images in the c-c and ml planes (2D) and in the c-c and c-c planes with an angle of 4 degrees (3D). Five radiologists experienced in mammography (experience ranging from 3 months to more than 5 years) analyzed the images (monitoring) which had been randomly encoded (random generator) with regard to the recognition of details such as specks of aluminum oxide (200-740 µm), nylon fibers (0.4-1.6 mm) and round lesions/masses (diameters 5-14 mm), using special linear glasses for 3D visualization, and compared the results. Results: A total of 225 correct positive decisions could be detected: we found 222 (98.7 %) correct positive results for 2D and 3D visualization in each case. Conclusion: The results of this phantom study showed the same detection rates for both 2D and 3D imaging using full field digital mammography. Our results must be confirmed in further clinical trials.

  4. Computer-aided detection of masses in digital tomosynthesis mammography: combination of 3D and 2D detection information

    NASA Astrophysics Data System (ADS)

    Chan, Heang-Ping; Wei, Jun; Zhang, Yiheng; Moore, Richard H.; Kopans, Daniel B.; Hadjiiski, Lubomir; Sahiner, Berkman; Roubidoux, Marilyn A.; Helvie, Mark A.

    2007-03-01

    We are developing a computer-aided detection (CAD) system for masses on digital breast tomosynthesis mammograms (DBTs). The CAD system includes two parallel processes. In the first process, mass detection and feature analysis are performed in the reconstructed 3D DBT volume. A mass likelihood score is estimated for each mass candidate using a linear discriminant (LDA) classifier. In the second process, mass detection and feature analysis are applied to the individual projection view (PV) images. A mass likelihood score is estimated for each mass candidate using another LDA classifier. The mass likelihood images derived from the PVs are back-projected to the breast volume to estimate the 3D spatial distribution of the mass likelihood scores. The mass likelihood scores estimated by the two processes at the corresponding 3D location are then merged and evaluated using FROC analysis. In this preliminary study, a data set of 52 DBT cases acquired with a GE prototype system at the Massachusetts General Hospital was used. The LDA classifiers with stepwise feature selection were designed with leave-one-case-out resampling. In an FROC analysis, the CAD system for detection in the DBT volume alone achieved test sensitivities of 80% and 90% at an average FP rate of 1.6 and 3.0 per breast, respectively. In comparison, the average FP rates of the combined system were 1.2 and 2.3 per breast, respectively, at the same sensitivities. The combined system is a promising approach to improving mass detection on DBTs.

  5. Full Field Digital Mammography (FFDM) versus CMOS Technology versus Tomosynthesis (DBT) - Which System Increases the Quality of Intraoperative Imaging?

    PubMed

    Schulz-Wendtland, R; Dilbat, G; Bani, M; Fasching, P A; Lux, M P; Wenkel, E; Schwab, S; Loehberg, C R; Jud, S M; Rauh, C; Bayer, C M; Beckmann, M W; Uder, M; Meier-Meitinger, M

    2012-06-01

    Aim: The aim of this prospective clinical study was to assess whether it would be possible to reduce the rate of re-excisions and improve the quality using CMOS technology or digital breast tomosynthesis (DBT) compared to a conventional FFDM system. Material and Methods: An invasive breast cancer (BI-RADS 5) was diagnosed in 200 patients in the period from 5/2011 to 1/2012. After histological verification, a breast-conserving therapy was performed with intraoperative imaging. Three different imaging systems were used: 1) Inspiration™ (Siemens, Erlangen, Germany), amorphous selenium, tungsten source, focus 0.1 mm, resolution 85 µm pixel pitch, 8 l/mm as the standard; 2) BioVision™ (Bioptics, Tucson, USA), flat panel photodiode array, tungsten source, focus 0.05, resolution 50 µm pixel pitch, 12 l/mm; 3) Tomosynthesis (Siemens, Erlangen, Germany), amorphous selenium, tungsten source, focus 0.1 mm, resolution 85 µm pixel pitch, 8 l/mm, range: 50°, 25 projections, scan time > 20 s, geometry: uniform scanning, reconstruction: filtered back projection. The 600 radiograms were prospectively shown to 3 radiologists. Results: Out of a total of 200 patients with histologically confirmed breast cancer (BI-RADS 6) 156 patients required no further operative therapy (re-excision) after breast-conserving therapy. A retrospective analysis (n = 44) showed an increase in sensitivity with tomosynthesis compared to the BioVision™ (CMOS technology) and the Inspiration™ at a magnification of 1.0 : 1.0 of 8 % (p < 0.05), i.e. re-excision would not have been necessary in 16 patients with tomosynthesis. Conclusions: The sensitivity of tomosynthesis for intraoperative radiography is significantly (p < 0.05) higher compared to both CMOS technology and an FFDM system with a conventional detector. Additional studies using higher magnification, e.g. 2.0 : 1.0, but no zooming will be necessary to evaluate the method further.

  6. TU-CD-207-03: Time Evolution of Texture Parameters of Subtracted Images Obtained by Contrast-Enhanced Digital Mammography (CEDM)

    SciTech Connect

    Mateos, M-J; Brandan, M-E; Gastelum, A; Marquez, J

    2015-06-15

    Purpose: To evaluate the time evolution of texture parameters, based on the gray level co-occurrence matrix (GLCM), in subtracted images of 17 patients (10 malignant and 7 benign) subjected to contrast-enhanced digital mammography (CEDM). The goal is to determine the sensitivity of texture to iodine uptake at the lesion, and its correlation (or lack of) with mean-pixel-value (MPV). Methods: Acquisition of clinical images followed a single-energy CEDM protocol using Rh/Rh/48 kV plus external 0.5 cm Al from a Senographe DS unit. Prior to the iodine-based contrast medium (CM) administration a mask image was acquired; four CM images were obtained 1, 2, 3, and 5 minutes after CM injection. Temporal series were obtained by logarithmic subtraction of registered CM minus mask images.Regions of interest (ROI) for the lesion were drawn by a radiologist and the texture was analyzed. GLCM was evaluated at a 3 pixel distance, 0° angle, and 64 gray-levels. Pixels identified as registration errors were excluded from the computation. 17 texture parameters were chosen, classified according to similarity into 7 groups, and analyzed. Results: In all cases the texture parameters within a group have similar dynamic behavior. Two texture groups (associated to cluster and sum mean) show a strong correlation with MPV; their average correlation coefficient (ACC) is r{sup 2}=0.90. Other two groups (contrast, homogeneity) remain constant with time, that is, a low-sensitivity to CM uptake. Three groups (regularity, lacunarity and diagonal moment) are sensitive to CM uptake but less correlated with MPV; their ACC is r{sup 2}=0.78. Conclusion: This analysis has shown that, at least groups associated to regularity, lacunarity and diagonal moment offer dynamical information additional to the mean pixel value due to the presence of CM at the lesion. The next step will be the analysis in terms of the lesion pathology. Authors thank PAPIIT-IN105813 for support. Consejo Nacional de Ciencia Y

  7. Computer vision and artificial intelligence in mammography.

    PubMed

    Vyborny, C J; Giger, M L

    1994-03-01

    The revolution in digital computer technology that has made possible new and sophisticated imaging techniques may next influence the interpretation of radiologic images. In mammography, computer vision and artificial intelligence techniques have been used successfully to detect or to characterize abnormalities on digital images. Radiologists supplied with this information often perform better at mammographic detection or characterization tasks in observer studies than do unaided radiologists. This technology therefore could decrease errors in mammographic interpretation that continue to plague human observers.

  8. Grid infrastructures for developing mammography CAD systems.

    PubMed

    Ramos-Pollan, Raul; Franco, Jose M; Sevilla, Jorge; Guevara-Lopez, Miguel A; de Posada, Naimy Gonzalez; Loureiro, Joanna; Ramos, Isabel

    2010-01-01

    This paper presents a set of technologies developed to exploit Grid infrastructures for breast cancer CAD, that include (1) federated repositories of mammography images and clinical data over Grid storage, (2) a workstation for mammography image analysis and diagnosis and (3) a framework for data analysis and training machine learning classifiers over Grid computing power specially tuned for medical image based data. An experimental mammography digital repository of approximately 300 mammograms from the MIAS database was created and classifiers were built achieving a 0.85 average area under the ROC curve in a dataset of 100 selected mammograms with representative pathological lesions and normal cases. Similar results were achieved with classifiers built for the UCI Breast Cancer Wisconsin dataset (699 features vectors). Now these technologies are being validated in a real medical environment at the Faculty of Medicine in Porto University after a process of integrating the tools within the clinicians workflows and IT systems.

  9. Uncertainty modeling for ontology-based mammography annotation with intelligent BI-RADS scoring.

    PubMed

    Bulu, Hakan; Alpkocak, Adil; Balci, Pinar

    2013-05-01

    This paper presents an ontology-based annotation system and BI-RADS (Breast Imaging Reporting and Data System) score reasoning with Semantic Web technologies in mammography. The annotation system is based on the Mammography Annotation Ontology (MAO) where the BI-RADS score reasoning works. However, ontologies are based on crisp logic and they cannot handle uncertainty. Consequently, we propose a Bayesian-based approach to model uncertainty in mammography ontology and make reasoning possible using BI-RADS scores with SQWRL (Semantic Query-enhanced Web Rule Language). First, we give general information about our system and present details of mammography annotation ontology, its main concepts and relationships. Then, we express uncertainty in mammography and present approaches to handle uncertainty issues. System is evaluated with a manually annotated dataset DEMS (Dokuz Eylul University Mammography Set) and DDSM (Digital Database for Screening Mammography). We give the result of experimentations in terms of accuracy, sensitivity, precision and uncertainty level measures.

  10. CR mammography: Design and implementation of a quality control program

    SciTech Connect

    Moreno-Ramirez, A.; Brandan, M. E.; Villasenor-Navarro, Y.; Galvan, H. A.; Ruiz-Trejo, C.

    2012-10-23

    Despite the recent acquisition of significant quantities of computed radiography CR equipment for mammography, Mexican regulations do not specify the performance requirements for digital systems such as those of CR type. The design of a quality control program QCP specific for CR mammography systems was thus considered relevant. International protocols were taken as reference to define tests, procedures and acceptance criteria. The designed QCP was applied in three CR mammography facilities. Important deficiencies in spatial resolution, noise, image receptor homogeneity, artifacts and breast thickness compensation were detected.

  11. CR mammography: Design and implementation of a quality control program

    NASA Astrophysics Data System (ADS)

    Moreno-Ramírez, A.; Brandan, M. E.; Villaseñor-Navarro, Y.; Galván, H. A.; Ruiz-Trejo, C.

    2012-10-01

    Despite the recent acquisition of significant quantities of computed radiography CR equipment for mammography, Mexican regulations do not specify the performance requirements for digital systems such as those of CR type. The design of a quality control program QCP specific for CR mammography systems was thus considered relevant. International protocols were taken as reference to define tests, procedures and acceptance criteria. The designed QCP was applied in three CR mammography facilities. Important deficiencies in spatial resolution, noise, image receptor homogeneity, artifacts and breast thickness compensation were detected.

  12. FDA Certified Mammography Facilities

    MedlinePlus

    ... Program Consumer Information (MQSA) Search for a Certified Facility Share Tweet Linkedin Pin it More sharing options ... Email Print This list of FDA Certified Mammography Facilities is updated weekly. If you click on Search ...

  13. The mammography project at the SYRMEP beamline.

    PubMed

    Dreossi, D; Abrami, A; Arfelli, F; Bregant, P; Casarin, K; Chenda, V; Cova, M A; Longo, R; Menk, R-H; Quai, E; Quaia, E; Rigon, L; Rokvic, T; Sanabor, D; Tonutti, M; Tromba, G; Vascotto, A; Zanconati, F; Castelli, E

    2008-12-01

    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.

  14. Beyond the mammography debate: a moderate perspective.

    PubMed

    Kaniklidis, C

    2015-06-01

    After some decades of contention, one can almost despair and conclude that (paraphrasing) "the mammography debate you will have with you always." Against that sentiment, in this review I argue, after reflecting on some of the major themes of this long-standing debate, that we must begin to move beyond the narrow borders of claim and counterclaim to seek consensus on what the balance of methodologically sound and critically appraised evidence demonstrates, and also to find overlooked underlying convergences; after acknowledging the reality of some residual and non-trivial harms from mammography, to promote effective strategies for harm mitigation; and to encourage deployment of new screening modalities that will render many of the issues and concerns in the debate obsolete. To these ends, I provide a sketch of what this looking forward and beyond the current debate might look like, leveraging advantages from abbreviated breast magnetic resonance imaging technologies (such as the ultrafast and twist protocols) and from digital breast tomosynthesis-also known as three-dimensional mammography. I also locate the debate within the broader context of mammography in the real world as it plays out not for the disputants, but for the stakeholders themselves: the screening-eligible patients and the physicians in the front lines who are charged with enabling both the acts of screening and the facts of screening at their maximally objective and patient-accessible levels to facilitate informed decisions.

  15. Beyond the mammography debate: a moderate perspective

    PubMed Central

    Kaniklidis, C

    2015-01-01

    After some decades of contention, one can almost despair and conclude that (paraphrasing) “the mammography debate you will have with you always.” Against that sentiment, in this review I argue, after reflecting on some of the major themes of this long-standing debate, that we must begin to move beyond the narrow borders of claim and counterclaim to seek consensus on what the balance of methodologically sound and critically appraised evidence demonstrates, and also to find overlooked underlying convergences; after acknowledging the reality of some residual and non-trivial harms from mammography, to promote effective strategies for harm mitigation; and to encourage deployment of new screening modalities that will render many of the issues and concerns in the debate obsolete. To these ends, I provide a sketch of what this looking forward and beyond the current debate might look like, leveraging advantages from abbreviated breast magnetic resonance imaging technologies (such as the ultrafast and twist protocols) and from digital breast tomosynthesis—also known as three-dimensional mammography. I also locate the debate within the broader context of mammography in the real world as it plays out not for the disputants, but for the stakeholders themselves: the screening-eligible patients and the physicians in the front lines who are charged with enabling both the acts of screening and the facts of screening at their maximally objective and patient-accessible levels to facilitate informed decisions. PMID:26089721

  16. Physical measures of image quality in mammography

    NASA Astrophysics Data System (ADS)

    Chakraborty, Dev P.

    1996-04-01

    A recently introduced method for quantitative analysis of images of the American College of Radiology (ACR) mammography accreditation phantom has been extended to include signal- to-noise-ratio (SNR) measurements, and has been applied to survey the image quality of 54 mammography machines from 17 hospitals. Participants sent us phantom images to be evaluated for each mammography machine at their hospital. Each phantom was loaned to us for obtaining images of the wax insert plate on a reference machine at our institution. The images were digitized and analyzed to yield indices that quantified the image quality of the machines precisely. We have developed methods for normalizing for the variation of the individual speck sizes between different ACR phantoms, for the variation of the speck sizes within a microcalcification group, and for variations in overall speeds of the mammography systems. In terms of the microcalcification SNR, the variability of the x-ray machines was 40.5% when no allowance was made for phantom or mAs variations. This dropped to 17.1% when phantom variability was accounted for, and to 12.7% when mAs variability was also allowed for. Our work shows the feasibility of practical, low-cost, objective and accurate evaluations, as a useful adjunct to the present ACR method.

  17. [Influence of Detector Radiation Damage on CR Mammography Quality Control].

    PubMed

    Moriwaki, Atsumi; Ishii, Mie; Terazono, Shiho; Arao, Keiko; Ishii, Rie; Sanada, Taizo; Yoshida, Akira

    2016-05-01

    Recently, radiation damage to the detector apparatus employed in computed radiography (CR) mammography has become problematic. The CR system and the imaging plate (IP) applied to quality control (QC) program were also used in clinical mammography in our hospital, and the IP to which radiation damage has occurred was used for approximately 5 years (approximately 13,000 exposures). We considered using previously acquired QC image data, which is stored in a server, to investigate the influence of radiation damage to an IP. The mammography unit employed in this study was a phase contrast mammography (PCM) Mermaid (KONICA MINOLTA) system. The QC image was made newly, and it was output in the film, and thereafter the optical density of the step-phantom image was measured. An input (digital value)-output (optical density) conversion curve was plotted using the obtained data. The digital values were then converted to optical density values using a reference optical density vs. digital value curve. When a high radiation dose was applied directly, radiation damage occurred at a position on the IP where no object was present. Daily QC for mammography is conducted using an American College of Radiology (ACR) accreditation phantom and acrylic disc, and an environmental background density measurement is performed as one of the management indexes. In this study, the radiation damage sustained by the acrylic disc was shown to differ from that of the background. Thus, it was revealed that QC results are influenced by radiation damage.

  18. Small Field: dosimetry in electron disequilibrium region

    NASA Astrophysics Data System (ADS)

    Zhu, Timothy C.

    2010-11-01

    Small fields are more commonly used for radiation therapy because of the development of IMRT, stereotactic radiosurgery, and other special equipments such as Cyberknife and Tomotherapy. The dosimetry in the sub-centimeter field can result in substantial uncertainties because of the presence of electron disequilibrium due to the large dose gradients in the field. It is further complicated by the introduction of various radiation detectors, which usually perturb the conditions of disequilibrium. Hence additional corrections are required to maintain the dosimetric accuracy previously achieved for standard radiation dosimetry. A review of small field dosimetry provides some insights into the methods to characterize the detector convolution kernel and other methods to characterize detector perturbation effect.

  19. A glass-ceramic plate for mammography.

    SciTech Connect

    Johnson, J. A.; Schweizer, S.; Lubinsky, A. R.; Nuclear Engineering Division; Univ. of Paderborn; State Univ. of New York at Stony Brook

    2007-01-01

    We developed translucent glass-ceramic image plates for digital mammography. The glass ceramics are based on europium-doped fluorozirconate glasses, which were additionally doped with chlorine to initiate the nucleation of barium chloride nanoparticles therein. The X-ray image is stored in the form of stable electron-hole pairs, which can be read out afterwards with a scanning laser beam in a 'photostimulated luminescence' (PSL) process. Measurements of the required stimulating exposure, integrated PSL signal, and optical light spreading of the stimulating laser light were performed to allow projection of the detective quantum efficiency (DQE) for the proposed X-ray storage phosphor system. The projected DQE is compared with commercially available electronic mammography systems.

  20. Mean glandular doses in mammography: a comparison of values displayed by a mammography unit with in-house values, both using the method proposed by Dance.

    PubMed

    Pasicz, Katarzyna; Fabiszewska, Ewa; Grabska, Iwona; Skrzyński, Witold

    2016-09-01

    The purpose of this work is to compare the mean glandular dose (MGD) displayed by the mammography system and the MGD calculated according to the method proposed by Dance for women. This study also attempts to analyse whether the relationship between the calculated and the displayed values is constant and what factors influence this relationship. Material for this study included data from 1200 exposures (i.e. six series; each series consisting of 200 exposures) performed with one full-field digital mammography unit. Based on collected parameters of exposures, values of the MGD for individual mammography examinations were calculated according to the methods proposed by Dance. Obtained values of the MGD were compared with the values displayed by the mammography system. The MGD displayed by the mammography system and the MGD calculated according to the method proposed by Dance for women are significantly different. This result emphasises the importance of verifying MGD values for patient radiation protection, particularly after machine servicing.

  1. Clinical study in phase- contrast mammography: image-quality analysis.

    PubMed

    Longo, Renata; Tonutti, Maura; Rigon, Luigi; Arfelli, Fulvia; Dreossi, Diego; Quai, Elisa; Zanconati, Fabrizio; Castelli, Edoardo; Tromba, Giuliana; Cova, Maria A

    2014-03-06

    The first clinical study of phase-contrast mammography (PCM) with synchrotron radiation was carried out at the Synchrotron Radiation for Medical Physics beamline of the Elettra synchrotron radiation facility in Trieste (Italy) in 2006-2009. The study involved 71 patients with unresolved breast abnormalities after conventional digital mammography and ultrasonography exams carried out at the Radiology Department of Trieste University Hospital. These cases were referred for mammography at the synchrotron radiation facility, with images acquired using a propagation-based phase-contrast imaging technique. To investigate the contribution of phase-contrast effects to the image quality, two experienced radiologists specialized in mammography assessed the visibility of breast abnormalities and of breast glandular structures. The images acquired at the hospital and at the synchrotron radiation facility were compared and graded according to a relative seven-grade visual scoring system. The statistical analysis highlighted that PCM with synchrotron radiation depicts normal structures and abnormal findings with higher image quality with respect to conventional digital mammography.

  2. Constraints on small-field axion inflation

    NASA Astrophysics Data System (ADS)

    Kobayashi, Tatsuo; Oikawa, Akane; Omoto, Naoya; Otsuka, Hajime; Saga, Ikumi

    2017-03-01

    We study general class of small-field axion inflations, which are the mixture of polynomial and sinusoidal functions suggested by the natural and axion monodromy inflations. The axion decay constants leading to the successful axion inflations are severely constrained in order not to spoil the big bang nucleosynthesis and overproduce the isocurvature perturbation originating from the QCD axion. We in turn find that the cosmologically favorable axion decay constants are typically of order the grand unification scale or the string scale, which is consistent with the prediction of closed-string axions.

  3. Positron emission mammography imaging

    SciTech Connect

    Moses, William W.

    2003-10-02

    This paper examines current trends in Positron Emission Mammography (PEM) instrumentation and the performance tradeoffs inherent in them. The most common geometry is a pair of parallel planes of detector modules. They subtend a larger solid angle around the breast than conventional PET cameras, and so have both higher efficiency and lower cost. Extensions to this geometry include encircling the breast, measuring the depth of interaction (DOI), and dual-modality imaging (PEM and x-ray mammography, as well as PEM and x-ray guided biopsy). The ultimate utility of PEM may not be decided by instrument performance, but by biological and medical factors, such as the patient to patient variation in radiotracer uptake or the as yet undetermined role of PEM in breast cancer diagnosis and treatment.

  4. Mammography accreditation program

    SciTech Connect

    Wilcox, P.

    1993-12-31

    In the mid-1980`s, the movement toward the use of dedicated mammography equipment provided significant improvement in breast cancer detection. However, several studies demonstrated that this change was not sufficient to ensure optimal image quality at a low radiation dose. In particular, the 1985 Nationwide Evaluation of X-ray Trends identified the wide variations in image quality and radiation dose, even from dedicated units. During this time period, the American Cancer Society (ACS) launched its Breast Cancer Awareness Screening Campaign. However, there were concerns about the ability of radiology to respond to the increased demand for optimal screening examinations that would result from the ACS program. To respond to these concerns, the ACS and the American College of Radiology (ACR) established a joint committee on mammography screening in 1986. After much discussion, it was decided to use the ACR Diagnostic Practice Accreditation Program as a model for the development of a mammography accreditation program. However, some constraints were required in order to make the program meet the needs of the ACS. This voluntary, peer review program had to be timely and cost effective. It was determined that the best way to address these needs would be to conduct the program by mail. Finally, by placing emphasis on the educational nature of the program, it would provide an even greater opportunity for improving mammographic quality. The result of this effort was that, almost six years ago, in May 1987, the pilot study for the ACR Mammography Accreditation Program (MAP) began, and in August of that year, the first applications were received. In November 1987, the first 3-year accreditation certificates were awarded.

  5. Preheating after small-field inflation

    SciTech Connect

    Brax, Philippe; Mariadassou, Sophie

    2011-05-15

    Whereas preheating after chaotic and hybrid inflation models has been abundantly studied in the literature, preheating in small field inflation models, where the curvature of the inflaton potential is negative during inflation, remains less explored. In these models, a tachyonic instability at the end of inflation leads to a succession of exponentially large increases and decreases of the inflaton fluctuations as the inflaton condensate oscillates around the minimum of its potential. The net effect is a competition between low-momentum modes which grow and decrease significantly, and modes with higher momenta which grow less but also decrease less. We develop an analytical description of this process, which is analogous to the quantum mechanical problem of tunneling through a volcano-shaped potential. Depending on the parameters, preheating may be so efficient that it completes in less than one oscillation of the inflaton condensate. Preheating after small field inflation may also be followed by a long matter-dominated stage before the Universe thermalizes, depending on the energy scale of inflation and the details of the inflaton interactions. Finally, another feature of these models is that the spectrum of the inflaton fluctuations at the end of preheating may be peaked around the Hubble scale. In fact, because preheating starts when the second slow-roll parameter |{eta}| becomes of order unity while the first slow-roll parameter {epsilon} is still much smaller than 1, the Universe is still inflating during preheating and the modes amplified by the initial tachyonic instability leave the Hubble radius. This may lead to an abundant production of primordial black holes and gravitational waves with frequencies today which are naturally small enough to fall into the range accessible by high-sensitivity interferometric experiments.

  6. Last stand of single small field inflation

    NASA Astrophysics Data System (ADS)

    Bramante, Joseph; Lehman, Landon; Martin, Adam; Downes, Sean

    2014-07-01

    By incorporating both the tensor-to-scalar ratio and the measured value of the spectral index, we set a bound on solo small field inflation of Δϕ/mPl≥1.00√r/0.1 . Unlike previous bounds which require monotonic ɛV, |ηV|<1, and 60 e-folds of inflation, the bound remains valid for nonmonotonic ɛV, |ηV|≳1, and for inflation which occurs only over the eight e-folds which have been observed on the cosmic microwave background. The negative value of the spectral index over the observed eight e-folds is what makes the bound strong; we illustrate this by surveying single field models and finding that for r ≳0.1 and eight e-folds of inflation, there is no simple potential which reproduces observed cosmic microwave background perturbations and remains sub-Planckian. Models that are sub-Planckian after eight e-folds must be patched together with a second epoch of inflation that fills out the remaining ˜50 e-folds. This second, post-cosmic microwave background epoch is characterized by extremely small ɛV and therefore an increasing scalar power spectrum. Using the fact that large power can overabundantly produce primordial black holes, we bound the maximum energy level of the second phase of inflation.

  7. Automatic patient dose registry and clinical audit on line for mammography.

    PubMed

    Ten, J I; Vano, E; Sánchez, R; Fernandez-Soto, J M

    2015-07-01

    The use of automatic registry systems for patient dose in digital mammography allows clinical audit and patient dose analysis of the whole sample of individual mammography exposures while fulfilling the requirements of the European Directives and other international recommendations. Further parameters associated with radiation exposure (tube voltage, X-ray tube output and HVL values for different kVp and target/filter combinations, breast compression, etc.) should be periodically verified and used to evaluate patient doses. This study presents an experience in routine clinical practice for mammography using automatic systems.

  8. PATIENT EXPOSURE DURING PLAIN RADIOGRAPHY AND MAMMOGRAPHY IN JAPAN IN 1974-2014.

    PubMed

    Matsunaga, Yuta; Kawaguchi, Ai; Kobayashi, Kenichi; Kobayashi, Masanao; Asada, Yasuki; Minami, Kazuyuki; Suzuki, Shoichi; Chida, Koichi

    2017-03-01

    We investigated changes in the entrance skin dose (ESD) and the mean glandular dose (MGD) during plain radiography or mammography in Japan from 1974 to 2014. Surveys regarding the conditions used for plain radiography and mammography were performed throughout Japan in 1974, 1979, 1989, 1993, 1997, 2001, 2003, 2007, 2011 and 2014. The anatomical regions considered were categorised as follows: skull anteroposterior (AP), lumbar AP, lumbar lateral (LAT), pelvis (AP), ankle, chest posteroanterior (PA), Guthmann (lateral pelviography for pregnant women), infant hip joint and mammography. The doses for all anatomical regions decreased from 1974 to 1993. The MGD for mammography remained low from 1993 to 2014, and the ESDs for chest (PA) radiography trended upward. After the 2000s, the use of digital imaging increased in Japan. This is the first long-term study to examine changes in ESDs and MGDs in Japan.

  9. Measurement of the radiation dose and assessment of the risk in mammography screening for early detection of cancer of the breast, in Israel.

    PubMed

    Broisman, A; Schlesinger, T; Alfassi, Z B

    2011-01-01

    The mean glandular doses to samples of women attending for mammographic screening are measured routinely at screening centres in Israel. As at present, no detailed and systematic data have been collected regarding the average glandular dose in mammography screening procedures carried out in Israel for the last 20 y. Especially data are lacking related to the glandular dose (GD) involved in mammography with the new digital mammography systems. In this work, partial results of the measurements are presented to asses the radiation dose to the breast and to the glandular tissue within the Israeli national mammography programme updated to year 2009.

  10. Database-Aided Diagnosis in Digital Mammography

    DTIC Science & Technology

    2001-07-01

    panel of radiologists consisted of Anthony C. Disher, MD, Robert C. Murchison, MD, Janis F. Owens, MD, and Carolyn R. Towler, MD. Jack I. Eisenman...Database-Aided Decisions," 1997. J. Ribas -Corbera, "Image Data Compress and Interframe Interpolation of Cinematic Sequences," 1992. M. R. Vriesenga...Cinematic Sequences" (with J. Ribas -Corbera), Journal of Visual Communication and Image Representation, Vol. 4, No. 4, December 1993, pp. 392-406. 13

  11. Quality Imaging — Comparison of CR Mammography with Screen-Film Mammography

    NASA Astrophysics Data System (ADS)

    Gaona, E.; Azorín Nieto, J.; Irán Díaz Góngora, J. A.; Arreola, M.; Casian Castellanos, G.; Perdigón Castañeda, G. M.; Franco Enríquez, J. G.

    2006-09-01

    The aim of this work is a quality imaging comparison of CR mammography images printed to film by a laser printer with screen-film mammography. A Giotto and Elscintec dedicated mammography units with fully automatic exposure and a nominal large focal spot size of 0.3 mm were used for the image acquisition of phantoms in screen-film mammography. Four CR mammography units from two different manufacturers and three dedicated x-ray mammography units with fully automatic exposure and a nominal large focal spot size of 0.3 mm were used for the image acquisition of phantoms in CR mammography. The tests quality image included an assessment of system resolution, scoring phantom images, Artifacts, mean optical density and density difference (contrast). In this study, screen-film mammography with a quality control program offers a significantly greater level of quality image relative to CR mammography images printed on film.

  12. Image and Dose Simulation in Support of New Mammography Modalities

    SciTech Connect

    Kuruvilla Verghese

    2002-04-05

    This report summarizes the highlights of the research performed under the 2-year NEER grant from the Department of Energy. The primary outcome of the work was a new Monte Carlo code, MCMIS-DS, for Monte Carlo for Mammography Image Simulation including Differential Sampling. The code was written to generate simulated images and dose distributions from two different new digital x-ray imaging modalities, namely, synchrotron imaging (SI) and a slot geometry digital mammography system called Fisher Senoscan. A differential sampling scheme was added to the code to generate multiple images that included variations in the parameters of the measurement system and the object in a single execution of the code. The code is to serve multiple purposes; (1) to answer questions regarding the contribution of scattered photons to images, (2) for use in design optimization studies, and (3) to do up to second-order perturbation studies to assess the effects of design parameter variations and/or physical parameters of the object (the breast) without having to re-run the code for each set of varied parameters. The accuracy and fidelity of the code were validated by a large variety of benchmark studies using published data and also using experimental results from mammography phantoms on both imaging modalities.

  13. Breast Cancer and Mammography: Summary of the Educational Impact of a Low-Cost Mammography Program.

    ERIC Educational Resources Information Center

    Gresham, Louise S.; And Others

    1988-01-01

    A mammography public education program which used newspaper press releases, local talk shows, news segments, and announcements, flyers, advertisements, and presentations to companies and select populations increased public awareness and decreased misconceptions about mammography. (CB)

  14. Phase mammography - a new technique for breast investigation

    NASA Astrophysics Data System (ADS)

    Ingal, Viktor N.; Beliaevskaya, Elena A.; Brianskaya, Alla P.; Merkurieva, Raisa D.

    1998-09-01

    A new phase radiography technique for investigation and diagnosis of neoplasms in breast tissue is proposed. Forty-four mammography samples with adenocarcinoma that had been prepared after mastectomy were tested in a new phase radiography device. It was shown that the phase images manifest the changes in parenchyma structure due to malignancy and microcalcifications up to in size. Results obtained were verified by histological examination. A contrast of the phase images of small microcalcifications and distortions of the stroma architecture ranges up to 40-60%; spatial resolution is about . The proposed technique offers outstanding possibilities for digital mammography. The small and large details of structure manifest themselves with practically the same contrast. Phase images differ from those obtained in mammography and many details still require further decoding.

  15. Frequency-Domain Optical Mammography

    DTIC Science & Technology

    2001-10-01

    optical measurements on breast-like phantoms (Months 19-24) a. Prepare the breast-like phantoms (optical inhomogeneities + strongly scattering...reveals contralateral hemodynamic changes upon hemi- imaging of solid phantoms for optical mammography. Appl Opt field paradigm. Vision Res 41: 97...1064 nm for the Nd:YAG, 660-1180 nm (tunable) for the Ti:sapphire, and 625-780 nm (tunable) for dye lasers using DCM or oxanine 1 dyes. A unique

  16. Rayleigh imaging in spectral mammography

    NASA Astrophysics Data System (ADS)

    Berggren, Karl; Danielsson, Mats; Fredenberg, Erik

    2016-03-01

    Spectral imaging is the acquisition of multiple images of an object at different energy spectra. In mammography, dual-energy imaging (spectral imaging with two energy levels) has been investigated for several applications, in particular material decomposition, which allows for quantitative analysis of breast composition and quantitative contrast-enhanced imaging. Material decomposition with dual-energy imaging is based on the assumption that there are two dominant photon interaction effects that determine linear attenuation: the photoelectric effect and Compton scattering. This assumption limits the number of basis materials, i.e. the number of materials that are possible to differentiate between, to two. However, Rayleigh scattering may account for more than 10% of the linear attenuation in the mammography energy range. In this work, we show that a modified version of a scanning multi-slit spectral photon-counting mammography system is able to acquire three images at different spectra and can be used for triple-energy imaging. We further show that triple-energy imaging in combination with the efficient scatter rejection of the system enables measurement of Rayleigh scattering, which adds an additional energy dependency to the linear attenuation and enables material decomposition with three basis materials. Three available basis materials have the potential to improve virtually all applications of spectral imaging.

  17. Small field axion inflation with sub-Planckian decay constant

    SciTech Connect

    Kadota, Kenji; Kobayashi, Tatsuo; Oikawa, Akane; Omoto, Naoya; Otsuka, Hajime; Tatsuishi, Takuya H.

    2016-10-10

    We study an axion inflation model recently proposed within the framework of type IIB superstring theory, where we pay a particular attention to a sub-Planckian axion decay constant. Our axion potential can lead to the small field inflation with a small tensor-to-scalar ratio, and a typical reheating temperature can be as low as GeV.

  18. Small field axion inflation with sub-Planckian decay constant

    NASA Astrophysics Data System (ADS)

    Kadota, Kenji; Kobayashi, Tatsuo; Oikawa, Akane; Omoto, Naoya; Otsuka, Hajime; Tatsuishi, Takuya H.

    2016-10-01

    We study an axion inflation model recently proposed within the framework of type IIB superstring theory, where we pay a particular attention to a sub-Planckian axion decay constant. Our axion potential can lead to the small field inflation with a small tensor-to-scalar ratio, and a typical reheating temperature can be as low as GeV.

  19. Barriers to Mammography among Inadequately Screened Women

    ERIC Educational Resources Information Center

    Stoll, Carolyn R. T.; Roberts, Summer; Cheng, Meng-Ru; Crayton, Eloise V.; Jackson, Sherrill; Politi, Mary C.

    2015-01-01

    Mammography use has increased over the past 20 years, yet more than 30% of women remain inadequately screened. Structural barriers can deter individuals from screening, however, cognitive, emotional, and communication barriers may also prevent mammography use. This study sought to identify the impact of number and type of barriers on mammography…

  20. Small field dosimetric characterization of a new 160-leaf MLC

    NASA Astrophysics Data System (ADS)

    Cranmer-Sargison, G.; Liu, P. Z. Y.; Weston, S.; Suchowerska, N.; Thwaites, D. I.

    2013-10-01

    The goal of this work was to perform a 6 MV small field characterization of the new Agility 160-leaf multi-leaf collimator (MLC) from Elekta. This included profile measurement analysis and central axis relative output measurements using various diode detectors and an air-core fiber optic scintillation dosimeter (FOD). Data was acquired at a depth of 10.0 cm for field sizes of 1.0, 0.9, 0.8, 0.7, 0.6 and 0.5 cm. Three experimental data sets, comprised of five readings, were made for both the relative output and profile measurements. Average detector-specific output ratios (\\overline {OR} _{det}^{f_{clin} }) were calculated with respect to a field size of 3.0 cm and small field replacement correction factors (\\mathop k\

  1. Dual-energy contrast-enhanced mammography.

    PubMed

    Travieso Aja, M M; Rodríguez Rodríguez, M; Alayón Hernández, S; Vega Benítez, V; Luzardo, O P

    2014-01-01

    The degree of vascularization in breast lesions is related to their malignancy. For this reason, functional diagnostic imaging techniques have become important in recent years. Dual-energy contrast-enhanced mammography is a new, apparently promising technique in breast cancer that provides information about the degree of vascularization of the lesion in addition to the morphological information provided by conventional mammography. This article describes the state of the art for dual-energy contrast-enhanced mammography. Based on 15 months' clinical experience, we illustrate this review with clinical cases that allow us to discuss the advantages and limitations of this technique.

  2. Family/friend recommendations and mammography intentions: the roles of perceived mammography norms and support

    PubMed Central

    Molina, Yamile; Ornelas, India J.; Doty, Sarah L.; Bishop, Sonia; Beresford, Shirley A. A.; Coronado, Gloria D.

    2015-01-01

    Identifying factors that increase mammography use among Latinas is an important public health priority. Latinas are more likely to report mammography intentions and use, if a family member or friend recommends that they get a mammogram. Little is known about the mechanisms underlying the relationship between social interactions and mammography intentions. Theory suggests that family/friend recommendations increase perceived mammography norms (others believe a woman should obtain a mammogram) and support (others will help her obtain a mammogram), which in turn increase mammography intentions and use. We tested these hypotheses with data from the ¡Fortaleza Latina! study, a randomized controlled trial including 539 Latinas in Washington State. Women whose family/friend recommended they get a mammogram within the last year were more likely to report mammography intentions, norms and support. Perceived mammography norms mediated the relationship between family/friend recommendations and intentions, Mediated Effect = 0.38, 95%CI [0.20, 0.61], but not support, Mediated Effect = 0.002, 95%CI [−0.07, 0.07]. Our findings suggest perceived mammography norms are a potential mechanism underlying the effect of family/friend recommendations on mammography use among Latinas. Our findings make an important contribution to theory about the associations of social interactions, perceptions and health behaviors. PMID:26324395

  3. Family/friend recommendations and mammography intentions: the roles of perceived mammography norms and support.

    PubMed

    Molina, Yamile; Ornelas, India J; Doty, Sarah L; Bishop, Sonia; Beresford, Shirley A A; Coronado, Gloria D

    2015-10-01

    Identifying factors that increase mammography use among Latinas is an important public health priority. Latinas are more likely to report mammography intentions and use, if a family member or friend recommends that they get a mammogram. Little is known about the mechanisms underlying the relationship between social interactions and mammography intentions. Theory suggests that family/friend recommendations increase perceived mammography norms (others believe a woman should obtain a mammogram) and support (others will help her obtain a mammogram), which in turn increase mammography intentions and use. We tested these hypotheses with data from the ¡Fortaleza Latina! study, a randomized controlled trial including 539 Latinas in Washington State. Women whose family/friend recommended they get a mammogram within the last year were more likely to report mammography intentions, norms and support. Perceived mammography norms mediated the relationship between family/friend recommendations and intentions, Mediated Effect = 0.38, 95%CI [0.20, 0.61], but not support, Mediated Effect = 0.002, 95%CI [-0.07, 0.07]. Our findings suggest perceived mammography norms are a potential mechanism underlying the effect of family/friend recommendations on mammography use among Latinas. Our findings make an important contribution to theory about the associations of social interactions, perceptions and health behaviors.

  4. TU-EF-207-02: Spectral Mammography Based on Photon Counting Detectors

    SciTech Connect

    Molloi, S.

    2015-06-15

    Breast imaging technology is advancing on several fronts. In digital mammography, the major technological trend has been on optimization of approaches for performing combined mammography and tomosynthesis using the same system. In parallel, photon-counting slot-scan mammography is now in clinical use and more efforts are directed towards further development of this approach for spectral imaging. Spectral imaging refers to simultaneous acquisition of two or more energy-windowed images. Depending on the detector and associated electronics, there are a number of ways this can be accomplished. Spectral mammography using photon-counting detectors can suppress electronic noise and importantly, it enables decomposition of the image into various material compositions of interest facilitating quantitative imaging. Spectral imaging can be particularly important in intravenously injected contrast mammography and eventually tomosynthesis. The various approaches and applications of spectral mammography are discussed. Digital breast tomosynthesis relies on the mechanical movement of the x-ray tube to acquire a number of projections in a predefined arc, typically from 9 to 25 projections over a scan angle of +/−7.5 to 25 degrees depending on the particular system. The mechanical x-ray tube motion requires relatively long acquisition time, typically between 3.7 to 25 seconds depending on the system. Moreover, mechanical scanning may have an effect on the spatial resolution due to internal x-ray filament or external mechanical vibrations. New x-ray source arrays have been developed and they are aimed at replacing the scanned x-ray tube for improved acquisition time and potentially for higher spatial resolution. The potential advantages and challenges of this approach are described. Combination of digital mammography and tomosynthesis in a single system places increased demands on certain functional aspects of the detector and overall performance, particularly in the tomosynthesis

  5. Mammography screening services: market segments and messages.

    PubMed

    Scammon, D L; Smith, J A; Beard, T

    1991-01-01

    Mammography has become a vital tool for the early detection of breast cancer. Although many organizations and health care facilities are working to educate and motivate women to take advantage of the life saving opportunity that is offered through screening mammography, only twenty percent of women who should be screened actually have the procedure performed. In order to reach women who have not been screened, it is important to learn which factors most strongly motivate those women who do choose to have a mammogram. Depth interviews with 18 women attending a mobile mammography unit were conducted to explore the decision making process of women obtaining mammography screening services and to develop a profile of prevalent emotions, attitudes, and feelings associated with receiving breast cancer screening services. Analysis of the interview transcripts revealed several important themes to which health care professionals can direct marketing and health promotion strategies.

  6. Benefits and harms of mammography screening.

    PubMed

    Løberg, Magnus; Lousdal, Mette Lise; Bretthauer, Michael; Kalager, Mette

    2015-05-01

    Mammography screening for breast cancer is widely available in many countries. Initially praised as a universal achievement to improve women's health and to reduce the burden of breast cancer, the benefits and harms of mammography screening have been debated heatedly in the past years. This review discusses the benefits and harms of mammography screening in light of findings from randomized trials and from more recent observational studies performed in the era of modern diagnostics and treatment. The main benefit of mammography screening is reduction of breast-cancer related death. Relative reductions vary from about 15 to 25% in randomized trials to more recent estimates of 13 to 17% in meta-analyses of observational studies. Using UK population data of 2007, for 1,000 women invited to biennial mammography screening for 20 years from age 50, 2 to 3 women are prevented from dying of breast cancer. All-cause mortality is unchanged. Overdiagnosis of breast cancer is the main harm of mammography screening. Based on recent estimates from the United States, the relative amount of overdiagnosis (including ductal carcinoma in situ and invasive cancer) is 31%. This results in 15 women overdiagnosed for every 1,000 women invited to biennial mammography screening for 20 years from age 50. Women should be unpassionately informed about the benefits and harms of mammography screening using absolute effect sizes in a comprehensible fashion. In an era of limited health care resources, screening services need to be scrutinized and compared with each other with regard to effectiveness, cost-effectiveness and harms.

  7. Mammography, thermography, and ultrasound in breast cancer detection

    SciTech Connect

    Basset, L.W.; Gold, R.H.

    1982-01-01

    The book begins with a brief discussion of the history of mammography and a good review and discussion of the mammorgraphy controversy. The section on diagnosis is excellent with very good anatomic-pathologic correlation of the mammography signs. The preoperative localization is well described. Section 3 on performing the examination is an excellent discussion of the various modes of mammography and their techniques. Magnification mammography, computed tomographic mammography, thermography, sonomammography, and ductography are very well covered. In Section 4, the benefits and risk of mammography are well discussed enabling the reader to understand the controversy surrounding breast cancer detection techniques.

  8. [New mammography technologies and their impact on radiation dose].

    PubMed

    Chevalier del Rio, M

    2013-12-01

    This article reviews new mammography technologies resulting from advances in digital detectors and processing techniques. Most are just starting to be commercialized or are in the clinical trial phase. The results of clinical trials with the new 2D techniques (contrast-enhanced techniques or stereotactic techniques) show they are useful for diagnosing cancer. However, the greater complexity of the image acquisition process suggests that their use will be limited to particular cases such as inconclusive lesions or women with high risk for developing breast cancer. Among the 3D technologies (breast tomography and breast tomosynthesis), only breast tomosynthesis has been implemented in clinical practice, so it is the only technique for which it is possible to know the sensitivity, specificity, and radiation dose delivered. This article describes the principles underlying the way breast tomosynthesis works and the techniques used for image acquisition and reconstruction. It also summarizes the main results obtained in clinical studies, which generally show that breast tomosynthesis increases the breast cancer detection rate while decreasing the recall rate and number of biopsies taken. The protocol for breast tomosynthesis approved by the Food and Drug Administration (USA) consists of two conventional mammography projections for each breast and two tomosynthesis projections for each breast. This means multiplying the risks of inducing cancer and death associated with 2D mammography by a factor between 2 and 3 (2.6-3.3 and 0.7-0.9 per 100,000 women exposed when 50 years old, respectively). The protocol for breast tomosynthesis examinations is one of the aspects that is essential to determine when including tomosynthesis in screening programs and routine breast imaging.

  9. Family/Friend Recommendations and Mammography Intentions: The Roles of Perceived Mammography Norms and Support

    ERIC Educational Resources Information Center

    Molina, Yamile; Ornelas, India J.; Doty, Sarah L.; Bishop, Sonia; Beresford, Shirley A. A.; Coronado, Gloria D.

    2015-01-01

    Identifying factors that increase mammography use among Latinas is an important public health priority. Latinas are more likely to report mammography intentions and use, if a family member or friend recommends that they get a mammogram. Little is known about the mechanisms underlying the relationship between social interactions and mammography…

  10. Visibility of microcalcifications in computed and screen-film mammography

    NASA Astrophysics Data System (ADS)

    Cowen, Arnold R.; Launders, Jason H.; Jadav, Mark; Brettle, David S.

    1997-08-01

    Due to the clinically and technically demanding nature of breast x-ray imaging, mammography still remains one of the few essentially film-based radiological imaging techniques in modern medical imaging. There are a range of possible benefits available if a practical and economical direct digital imaging technique can be introduced to routine clinical practice. There has been much debate regarding the minimum specification required for direct digital acquisition. One such direct digital system available is computed radiography (CR), which has a modest specification when compared with modern screen-film mammography (SFM) systems. This paper details two psychophysical studies in which the detection of simulated microcalcifications with CR has been directly compared to that with SFM. The first study found that under scatter-free conditions the minimum detectable size of microcalcification was approximately for both SFM and CR. The second study found that SFM had a 4.6% higher probability of observers being able to correctly identify the shape of diameter test details; there was no significant difference for either larger or smaller test details. From the results of these studies it has been demonstrated that the modest specification of CR, in terms of limiting resolution, does not translate into a dramatic difference in the perception of details at the limit of detectability. When judging the imaging performance of a system it is more important to compare the signal-to-noise ratio transfer spectrum characteristics, rather than simply the modulation transfer function.

  11. Performance characterization of computed radiography based mammography systems

    NASA Astrophysics Data System (ADS)

    Singh, Abhinav; Desai, Nikunj; Valentino, Daniel J.

    2010-04-01

    Computed Radiography (CR) is a cost-effective technology for digital mammography. In order to optimize the quality of images obtained using CR Mammography, we characterized the effect on image quality of the electrooptical components of the CR imaging chain. The metrics used to assess the image quality included the Contrast to Noise Ratio (CNR), Modulation Transfer Function (MTF), Noise Power Spectrum (NPS), Detective Quantum Efficiency (DQE) and Contrast Detail Response Phantom (CDMAM 3.4 Artinis Medical Systems). An 18×24 cm high-resolution granular phosphor imaging plate (AGFA MM3.0) was used to acquire the images. Contrast detail was measured using a GUI developed for the CDMAM phantom that was scored by independent observers. The range of theoretically acceptable values measured for the CR laser was (5-36) mW and voltage range for PMT's was (4-8) V. The light detection amplifier was investigated, and the optimal Laser Power and PMT gain used for scanning was measured. The tools that we used (CNR, MTF, NPS, DQE and Contrast-detail phantom) provided an effective means of selecting optimal values for the electro-optical components of the system. The procedure enabled us to obtain good quality CR mammograms that have less noise and improved contrast.

  12. Cosmic microwave background observables of small field models of inflation

    SciTech Connect

    Ben-Dayan, Ido; Brustein, Ram E-mail: ramyb@bgu.ac.il

    2010-09-01

    We construct a class of single small field models of inflation that can predict, contrary to popular wisdom, an observable gravitational wave signal in the cosmic microwave background anisotropies. The spectral index, its running, the tensor to scalar ratio and the number of e-folds can cover all the parameter space currently allowed by cosmological observations. A unique feature of models in this class is their ability to predict a negative spectral index running in accordance with recent cosmic microwave background observations. We discuss the new class of models from an effective field theory perspective and show that if the dimensionless trilinear coupling is small, as required for consistency, then the observed spectral index running implies a high scale of inflation and hence an observable gravitational wave signal. All the models share a distinct prediction of higher power at smaller scales, making them easy targets for detection.

  13. Practical considerations for electron beam small field size dosimetry

    SciTech Connect

    Sharma, Subhash C.; Johnson, Martin W.; Gossman, Michael S. . E-mail: GossmanMS@erlanger.org

    2005-06-30

    Special care of superficial lesions surrounding critical structures, such as an eye, may require tight margins. When this is the case, small megavoltage electron treatment fields and nonstandard treatment distances become necessary. When the field size is found to be less than the practical range of the electron beam, dosimetric measurements should be performed. This research includes data proving that very small electron fields can be employed for treatment with appropriate beam flatness and penumbra. This is accomplished by first coning down the incident beam to a small field size, then secondly by adding a single lead sheet to the patient's skin surface. The aperture of the sheet is required to be greater than 2 x 2 cm{sup 2} in size, and must be cut properly to adequately confine the treatment area.

  14. Breast dosimetry in clinical mammography

    NASA Astrophysics Data System (ADS)

    Benevides, Luis Alberto Do Rego

    The objective of this study was show that a clinical dosimetry protocol that utilizes a dosimetric breast phantom series based on population anthropometric measurements can reliably predict the average glandular dose (AGD) imparted to the patient during a routine screening mammogram. In the study, AGD was calculated using entrance skin exposure and dose conversion factors based on fibroglandular content, compressed breast thickness, mammography unit parameters and modifying parameters for homogeneous phantom (phantom factor), compressed breast lateral dimensions (volume factor) and anatomical features (anatomical factor). The protocol proposes the use of a fiber-optic coupled (FOCD) or Metal Oxide Semiconductor Field Effect Transistor (MOSFET) dosimeter to measure the entrance skin exposure at the time of the mammogram without interfering with diagnostic information of the mammogram. The study showed that FOCD had sensitivity with less than 7% energy dependence, linear in all tube current-time product stations, and was reproducible within 2%. FOCD was superior to MOSFET dosimeter in sensitivity, reusability, and reproducibility. The patient fibroglandular content was evaluated using a calibrated modified breast tissue equivalent homogeneous phantom series (BRTES-MOD) designed from anthropomorphic measurements of a screening mammography population and whose elemental composition was referenced to International Commission on Radiation Units and Measurements Report 44 tissues. The patient fibroglandular content, compressed breast thickness along with unit parameters and spectrum half-value layer were used to derive the currently used dose conversion factor (DgN). The study showed that the use of a homogeneous phantom, patient compressed breast lateral dimensions and patient anatomical features can affect AGD by as much as 12%, 3% and 1%, respectively. The protocol was found to be superior to existing methodologies. In addition, the study population anthropometric

  15. Mammography calibration qualities establishment in a Mo- Mo clinical system

    NASA Astrophysics Data System (ADS)

    Corrêa, E. L.; dos Santos, L. R.; Vivolo, V.; Potiens, M. P. A.

    2016-07-01

    In this study the mammography calibration qualities were established in a clinical mammography system. The objective is to provide the IPEN instruments calibration laboratory with both mammography calibration methods (using a clinical and an industrial system). The results showed a good behavior of mammography equipment, in terms of kVp, PPV and exposure time. The additional filtration of molybdenum is adequate, air-kerma rates were determined and spectra were obtained.

  16. With the Advent of Tomosynthesis in the Workup of Mammographic Abnormality, is Spot Compression Mammography Now Obsolete? An Initial Clinical Experience.

    PubMed

    Ni Mhuircheartaigh, Neasa; Coffey, Louise; Fleming, Hannah; O' Doherty, Ann; McNally, Sorcha

    2017-03-02

    To determine if the routine use of spot compression mammography is now obsolete in the assessment of screen detected masses, asymmetries and architectural distortion since the availability of digital breast tomosynthesis. We introduced breast tomosynthesis in the workup of screen detected abnormalities in our screening center in January 2015. During an initial learning period with tomosynthesis standard spot compression views were also performed. Three consultant breast radiologists retrospectively reviewed all screening mammograms recalled for assessment over the first 6-month period. We assessed retrospectively whether there was any additional diagnostic information obtained from spot compression views not already apparent on tomography. All cases were also reviewed for any additional lesions detected by tomosynthesis, not detected on routine 2-view screening mammography. 548 women screened with standard 2-view digital screening mammography were recalled for assessment in the selected period and a total of 565 lesions were assessed. 341 lesions were assessed by both tomosynthesis and routine spot compression mammography. The spot compression view was considered more helpful than tomosynthesis in only one patient. This was because the breast was inadequately positioned for tomosynthesis and the area in question was not adequately imaged. Apart from this technical error there was no asymmetry, distortion or mass where spot compression provided more diagnostic information than tomosynthesis alone. We detected three additional cancers on tomosynthesis, not detected by routine screening mammography. From our initial experience with tomosynthesis we conclude that spot compression mammography is now obsolete in the assessment of screen detected masses, asymmetries and distortions where tomosynthesis is available.

  17. High-Resolution Mammography Detector Employing Optical Switching Readout

    NASA Astrophysics Data System (ADS)

    Irisawa, Kaku; Kaneko, Yasuhisa; Yamane, Katsutoshi; Sendai, Tomonari; Hosoi, Yuichi

    Conceiving a new detector structure, FUJIFILM Corporation has successfully put its invention of an X-ray detector employing "Optical Switching" into practical use. Since Optical Switching Technology allows an electrode structure to be easily designed, both high resolution of pixel pitch and low electrical noise readout have been achieved, which have consequently realized the world's smallest pixel size of 50×50 μm2 from a Direct-conversion FPD system as well as high DQE. The digital mammography system equipped with this detector enables to acquire high definition images while maintaining granularity. Its outstanding feature is to be able to acquire high-precision images of microcalcifications which is an important index in breast examination.

  18. Physical electrostatics of small field emitter arrays/clusters

    NASA Astrophysics Data System (ADS)

    Forbes, Richard G.

    2016-08-01

    This paper aims to improve qualitative understanding of electrostatic influences on apex field enhancement factors (AFEFs) for small field emitter arrays/clusters. Using the "floating sphere at emitter-plate potential" (FSEPP) model, it re-examines the electrostatics and mathematics of three simple systems of identical post-like emitters. For the isolated emitter, various approaches are noted. An adequate approximation is to consider only the effects of sphere charges and (for significantly separated emitters) image charges. For the 2-emitter system, formulas are found for charge-transfer ("charge-blunting") effects and neighbor-field effects, for widely spaced and for "sufficiently closely spaced" emitters. Mutual charge-blunting is always the dominant effect, with a related (negative) fractional AFEF-change δtwo. For sufficiently small emitter spacing c, |δtwo| varies approximately as 1/c; for large spacing, |δtwo| decreases as 1/c3. In a 3-emitter equispaced linear array, differential charge-blunting and differential neighbor-field effects occur, but differential charge-blunting effects are dominant, and cause the "exposed" outer emitters to have higher AFEF (γ0) than the central emitter (γ1). Formulas are found for the exposure ratio Ξ = γ0/γ1, for large and for sufficiently small separations. The FSEPP model for an isolated emitter has accuracy around 30%. Line-charge models (LCMs) are an alternative, but an apparent difficulty with recent LCM implementations is identified. Better descriptions of array electrostatics may involve developing good fitting equations for AFEFs derived from accurate numerical solution of Laplace's equation, perhaps with equation form(s) guided qualitatively by FSEPP-model results. In existing fitting formulas, the AFEF-reduction decreases exponentially as c increases, which is different from the FSEPP-model formulas. This discrepancy needs to be investigated, using systematic Laplace-based simulations and appropriate results

  19. Investigation of diagnostic and image quality attributes: comparison of screen-film to CR mammography

    NASA Astrophysics Data System (ADS)

    Fletcher-Heath, Lynn; Richards, Anne; Ryan-Kron, Susan

    2006-03-01

    Digital mammography is advancing into an arena where analog has long been the gold standard. Direct digital systems may not be the favored solution for a particular site while computed radiography (CR) mammography, remains unproven worldwide. This pilot study responds to the growing desire to acquire and display digital mammographic images by exploring the acceptability of CR mammography. Images representing a range of breast tissue types were collected from 49 subjects (17 screening; 32 diagnostic) at four clinical sites. Comparison views were collected on the same breast, under the same compression, using automatic exposure control on state-of-the-art film systems followed by CR. CR images were processed and printed to a mammography printer for hard copy feature comparison. Each image pair in the study was evaluated according to 13 image quality attributes covering noise, contrast, sharpness, and image quality in the overall captured images as well as in each of several particular breast regions (periphery and skin-line, parenchyma and fatty tissue). A rating scale from 1 to 5 was used (strong preference for film=1, strong preference for CR=5). Twelve experienced mammographers at four clinical sites scored a subset of the 49 cases for a total of 64 image pair readings. There were 64 ratings for each of 13 image quality attributes for all cases and, an additional series of scores (four or five attribute ratings) for each abnormality in the category of mass, architectural distortion and microcalcification, for a total of 1069 scores. Based on the pilot study results, it was suggested that CR was equivalent or preferred to conventional screen-film for overall image quality (38% scored 3; 46% scored >3), image contrast (27% scored 3; 59% scored >3) and sharpness (28% scored 3; 50% scored >3). No preference was found when assessing noise. This pilot study also suggested that diagnostic quality was maintained in assessing abnormalities for attributes necessary to

  20. Task-based strategy for optimized contrast enhanced breast imaging: Analysis of six imaging techniques for mammography and tomosynthesis

    SciTech Connect

    Ikejimba, Lynda C.; Kiarashi, Nooshin; Ghate, Sujata V.; Samei, Ehsan; Lo, Joseph Y.

    2014-06-15

    Purpose: The use of contrast agents in breast imaging has the capability of enhancing nodule detectability and providing physiological information. Accordingly, there has been a growing trend toward using iodine as a contrast medium in digital mammography (DM) and digital breast tomosynthesis (DBT). Widespread use raises concerns about the best way to use iodine in DM and DBT, and thus a comparison is necessary to evaluate typical iodine-enhanced imaging methods. This study used a task-based observer model to determine the optimal imaging approach by analyzing six imaging paradigms in terms of their ability to resolve iodine at a given dose: unsubtracted mammography and tomosynthesis, temporal subtraction mammography and tomosynthesis, and dual energy subtraction mammography and tomosynthesis. Methods: Imaging performance was characterized using a detectability index d{sup ′}, derived from the system task transfer function (TTF), an imaging task, iodine signal difference, and the noise power spectrum (NPS). The task modeled a 10 mm diameter lesion containing iodine concentrations between 2.1 mg/cc and 8.6 mg/cc. TTF was obtained using an edge phantom, and the NPS was measured over several exposure levels, energies, and target-filter combinations. Using a structured CIRS phantom, d{sup ′} was generated as a function of dose and iodine concentration. Results: For all iodine concentrations and dose, temporal subtraction techniques for mammography and tomosynthesis yielded the highest d{sup ′}, while dual energy techniques for both modalities demonstrated the next best performance. Unsubtracted imaging resulted in the lowest d{sup ′} values for both modalities, with unsubtracted mammography performing the worst out of all six paradigms. Conclusions: At any dose, temporal subtraction imaging provides the greatest detectability, with temporally subtracted DBT performing the highest. The authors attribute the successful performance to excellent cancellation of

  1. Task-based strategy for optimized contrast enhanced breast imaging: Analysis of six imaging techniques for mammography and tomosynthesis

    PubMed Central

    Ikejimba, Lynda C.; Kiarashi, Nooshin; Ghate, Sujata V.; Samei, Ehsan; Lo, Joseph Y.

    2014-01-01

    Purpose: The use of contrast agents in breast imaging has the capability of enhancing nodule detectability and providing physiological information. Accordingly, there has been a growing trend toward using iodine as a contrast medium in digital mammography (DM) and digital breast tomosynthesis (DBT). Widespread use raises concerns about the best way to use iodine in DM and DBT, and thus a comparison is necessary to evaluate typical iodine-enhanced imaging methods. This study used a task-based observer model to determine the optimal imaging approach by analyzing six imaging paradigms in terms of their ability to resolve iodine at a given dose: unsubtracted mammography and tomosynthesis, temporal subtraction mammography and tomosynthesis, and dual energy subtraction mammography and tomosynthesis. Methods: Imaging performance was characterized using a detectability index d′, derived from the system task transfer function (TTF), an imaging task, iodine signal difference, and the noise power spectrum (NPS). The task modeled a 10 mm diameter lesion containing iodine concentrations between 2.1 mg/cc and 8.6 mg/cc. TTF was obtained using an edge phantom, and the NPS was measured over several exposure levels, energies, and target-filter combinations. Using a structured CIRS phantom, d′ was generated as a function of dose and iodine concentration. Results: For all iodine concentrations and dose, temporal subtraction techniques for mammography and tomosynthesis yielded the highest d′, while dual energy techniques for both modalities demonstrated the next best performance. Unsubtracted imaging resulted in the lowest d′ values for both modalities, with unsubtracted mammography performing the worst out of all six paradigms. Conclusions: At any dose, temporal subtraction imaging provides the greatest detectability, with temporally subtracted DBT performing the highest. The authors attribute the successful performance to excellent cancellation of inplane structures and

  2. Elasto-Mammography: Elastic Property Reconstruction in Breast Tissues

    SciTech Connect

    Wang, Z. G.; Liu, Y.; Wang, G.; Sun, L. Z.

    2008-02-15

    Mammography is the primary method for screening and detecting breast cancers. However, it frequently fails to detect small tumors and is not quite specific in terms of tumor benignity and malignancy. The objective of this paper is to develop a new imaging modality called elasto-mammography that generates the modulus elastograms based on conventional mammographs. A new elastic reconstruction method is described based on elastography and mammography for breast tissues. Elastic distribution can be reconstructed through the measurement of displacement provided by mammographic projection. It is shown that the proposed elasto-mammography provides higher sensitivity and specificity than the conventional mammography on its own for breast cancer diagnosis.

  3. Pain with mammography: fact or fiction?

    PubMed

    Nielsen, B; Miaskowski, C; Dibble, S L

    1993-05-01

    This article presents an overview of current knowledge about mammography-related pain and discomfort. Possible causes of pain and discomfort are discussed along with the results of two pilot studies that investigated the prevalence and severity of pain and discomfort associated with film-screen mammograms in a mobile screening program. Based on these studies, the authors conclude that pain is a problem for a significant number of women from diverse ethnic and socioeconomic backgrounds. A nursing care plan is provided to assist nurses in reducing mammography-related pain and discomfort.

  4. Identifying Sociocultural Barriers to Mammography Adherence Among Appalachian Kentucky Women

    PubMed Central

    Cohen, Elisia L.; Wilson, Bethney R.; Vanderpool, Robin C.; Collins, Tom

    2016-01-01

    Despite lower breast cancer incidence rates, Appalachian women evidence lower frequency of screening mammography and higher mortality risk for breast cancer compared to non-Appalachian women in Kentucky, and in the United States, overall. Utilizing data from 27 in-depth interviews from women in seven Appalachian Kentucky counties, this study examines how Appalachian women explain sociocultural barriers and facilitators to timely screening mammography, and explores their common narratives about their mammography experiences. The women describe how pain and embarrassment, less personal and less professional mammography experiences, cancer fears, and poor provider communication pose barriers to timely and appropriate mammography schedule adherence and follow-up care. The study also identifies how improving communication strategies in the mammography encounter may improve mammography experiences and adherence to screening guidelines. PMID:25668682

  5. Identifying Sociocultural Barriers to Mammography Adherence Among Appalachian Kentucky Women.

    PubMed

    Cohen, Elisia L; Wilson, Bethney R; Vanderpool, Robin C; Collins, Tom

    2016-01-01

    Despite lower breast cancer incidence rates, Appalachian women evidence lower frequency of screening mammography and higher mortality risk for breast cancer compared to non-Appalachian women in Kentucky, and in the United States, overall. Utilizing data from 27 in-depth interviews from women in seven Appalachian Kentucky counties, this study examines how Appalachian women explain sociocultural barriers and facilitators to timely screening mammography, and explores their common narratives about their mammography experiences. The women describe how pain and embarrassment, less personal and less professional mammography experiences, cancer fears, and poor provider communication pose barriers to timely and appropriate mammography schedule adherence and follow-up care. The study also identifies how improving communication strategies in the mammography encounter may improve mammography experiences and adherence to screening guidelines.

  6. Three-dimensional mammography reconstruction using low-dose projection images

    NASA Astrophysics Data System (ADS)

    Wu, Tao

    A method is described for the reconstruction of three-dimensional distribution of attenuation coefficient of the breast using a limited number of low dose projection images. This method uses the cone beam x-ray geometry, a digital detector and a constrained iterative reconstruction algorithm. The method has been tested on a digital Tomosynthesis mammography system. The total radiation dose to the patient is comparable to that used for one conventional mammogram. The reconstructed image has intrinsically high resolution (˜0.1mm) in two dimensions and lower resolution in the third dimension (˜1mm). Using this method, a breast that is projected into one two-dimensional image in conventional mammography is separated into layers parallel to the two high-resolution dimensions. The thickness of the layer is in the low-resolution dimension. The three-dimensional reconstruction increases the conspicuity of features that is often obscured by overlapping tissues in a single projection. Factors affecting the quality of reconstruction have been investigated by computer simulations. These factors include the scatter, the projection angular range, the shape of the breast and the x-ray energy. Non-uniform distribution of x-ray exposures among projection images and non-uniform-resolution image-acquisition are explored to optimize the image quality within an x-ray dose limit. The method is validated with reconstruction images of mammography phantoms, mastectomy specimens, computer simulations and volunteer patients.

  7. Access to Mammography Facilities and Detection of Breast Cancer by Screening Mammography: A GIS Approach.

    PubMed

    Rahman, Selina; Price, James H; Dignan, Mark; Rahman, Saleh; Lindquist, Peter S; Jordan, Timothy R

    2009-01-01

    OBJECTIVES: The objective of the study was to examine the association between access to mammography facilities and utilization of screening mammography in an urban population. METHODS: Data on female breast cancer cases were obtained from an extensive mammography surveillance project. Distance to mammography facilities was measured by using GIS, which was followed by measuring geographical access to mammography facilities using Floating Catchment Area (FCA) method (considering all available facilities within an arbitrary radius from the woman's residence by using Arc GIS 9.0 software). RESULTS: Of 2,024 women, 91.4% were Caucasian; age ranged from 25 to 98 years; most (95%) were non-Hispanic in origin. Logistic regression found age, family history, hormone replacement therapy, physician recommendation, and breast cancer stage at diagnosis to be significant predictors of having had a previous mammogram. Women having higher access to mammography facilities were less likely to have had a previous mammogram compared to women who had low access, considering all the facilities within 10 miles (OR=0.41, CI=0.22-0.76), 30 miles (OR=0.52, CI=0.29-0.91) and 40 miles (OR=0.51, CI=0.28-0.92) radiuses. CONCLUSIONS: Physical distance to mammography facilities does not necessarily predict utilization of mammogram and greater access does not assure greater utilizations, due to constraints imposed by socio economic and cultural barriers. Future studies should focus on measuring access to mammography facilities capturing a broader dimension of access considering qualitative aspect of facilities, as well as other travel impedances.

  8. Screening Mammography in Older Women: A Review

    PubMed Central

    Walter, Louise C.; Schonberg, Mara A.

    2015-01-01

    Importance Guidelines recommend individualizing screening mammography decisions for women 75 and older. However, little pragmatic guidance is available to inform this approach. Objective To provide an evidence-based approach to individualizing decision-making about screening mammography that considers older women's risk of breast cancer and the potential benefits and harms of screening in the context of varying life expectancies and preferences. Evidence Acquisition We searched PubMed for English-language studies in peer-reviewed journals published from January 1, 1990 to February 1, 2014 to identify risk factors for late-life breast cancer in women 65 and older and to quantify the benefits and harms of screening mammography for women 75 and older. Findings Age is the major risk factor for late-life breast cancer. In general, traditional breast cancer risk factors (e.g., age at first birth, age at menarche) that represent hormonal exposures in the distant past are less predictive of late-life breast cancer than factors indicating recent exposure to endogenous hormones (e.g., bone mass, obesity). None of the randomized trials of screening mammography included women over age 74, such that it is uncertain whether screening mammography is beneficial in these women. Observational data favor extending screening mammography to older women who have a life expectancy > 5-10 years. Modeling studies suggest approximately 2 fewer women per 1,000 die from breast cancer if women in their 70's continue biennial screening for 10 years, versus stopping screening at age 69. Potential benefits must be weighed with potential harms of continued screening over ten years, which include false-positive mammograms (~200 per 1,000 women screened) and overdiagnosis (~13 per 1,000 women screened). Providing these frequencies both verbally and graphically may help inform older women's decision-making. Conclusions and Relevance For women with less than a 5-10 year life expectancy

  9. High dynamic range CMOS-based mammography detector for FFDM and DBT

    NASA Astrophysics Data System (ADS)

    Peters, Inge M.; Smit, Chiel; Miller, James J.; Lomako, Andrey

    2016-03-01

    Digital Breast Tomosynthesis (DBT) requires excellent image quality in a dynamic mode at very low dose levels while Full Field Digital Mammography (FFDM) is a static imaging modality that requires high saturation dose levels. These opposing requirements can only be met by a dynamic detector with a high dynamic range. This paper will discuss a wafer-scale CMOS-based mammography detector with 49.5 μm pixels and a CsI scintillator. Excellent image quality is obtained for FFDM as well as DBT applications, comparing favorably with a-Se detectors that dominate the X-ray mammography market today. The typical dynamic range of a mammography detector is not high enough to accommodate both the low noise and the high saturation dose requirements for DBT and FFDM applications, respectively. An approach based on gain switching does not provide the signal-to-noise benefits in the low-dose DBT conditions. The solution to this is to add frame summing functionality to the detector. In one X-ray pulse several image frames will be acquired and summed. The requirements to implement this into a detector are low noise levels, high frame rates and low lag performance, all of which are unique characteristics of CMOS detectors. Results are presented to prove that excellent image quality is achieved, using a single detector for both DBT as well as FFDM dose conditions. This method of frame summing gave the opportunity to optimize the detector noise and saturation level for DBT applications, to achieve high DQE level at low dose, without compromising the FFDM performance.

  10. SU-E-I-04: A Mammography Phantom to Measure Mean Glandular Dose and Image Quality

    SciTech Connect

    Lopez-Pineda, E; Ruiz-Trejo, C; E, Brandan M

    2014-06-01

    Purpose: To evaluate mean glandular dose (MGD) and image quality in a selection of mammography systems using a novel phantom based on thermoluminescent dosemeters and the ACR wax insert. Methods: The phantom consists of two acrylic, 19 cm diameter, 4.5 cm thick, semicircular modules, used in sequence. The image quality module contains the ACR insert and is used to obtain a quality control image under automatic exposure conditions. The dosimetric module carries 15 TLD-100 chips, some under Al foils, to determine air kerma and half-value-layer. TL readings take place at our laboratory under controlled conditions. Calibration was performed using an ionization chamber and a Senographe 2000D unit for a variety of beam qualities, from 24 to 40 kV, Mo and Rh anodes and filters. Phantom MGD values agree, on the average, within 3% with ionization chamber data, and their precision is better than 10% (k=1). Results: MGD and image quality have been evaluated in a selection of mammography units currently used in Mexican health services. The sample includes analogic (screen/film), flexible digital (CR), and full-field digital image receptors. The highest MDG are associated to the CR technology. The most common image quality failure is due to artifacts (dust, intensifying screen scratches, and processor marks for film/screen, laser reader defects for CR). Conclusion: The developed phantom permits the MGD measurement without the need of a calibrated ionization chamber at the mammography site and can be used by a technician without the presence of a medical physicist. The results indicate the urgent need to establish quality control programs for mammography.

  11. Limitations of analytical dose calculations for small field proton radiosurgery

    NASA Astrophysics Data System (ADS)

    Geng, Changran; Daartz, Juliane; Lam-Tin-Cheung, Kimberley; Bussiere, Marc; Shih, Helen A.; Paganetti, Harald; Schuemann, Jan

    2017-01-01

    The purpose of the work was to evaluate the dosimetric uncertainties of an analytical dose calculation engine and the impact on treatment plans using small fields in intracranial proton stereotactic radiosurgery (PSRS) for a gantry based double scattering system. 50 patients were evaluated including 10 patients for each of 5 diagnostic indications of: arteriovenous malformation (AVM), acoustic neuroma (AN), meningioma (MGM), metastasis (METS), and pituitary adenoma (PIT). Treatment plans followed standard prescription and optimization procedures for PSRS. We performed comparisons between delivered dose distributions, determined by Monte Carlo (MC) simulations, and those calculated with the analytical dose calculation algorithm (ADC) used in our current treatment planning system in terms of dose volume histogram parameters and beam range distributions. Results show that the difference in the dose to 95% of the target (D95) is within 6% when applying measured field size output corrections for AN, MGM, and PIT. However, for AVM and METS, the differences can be as great as 10% and 12%, respectively. Normalizing the MC dose to the ADC dose based on the dose of voxels in a central area of the target reduces the difference of the D95 to within 6% for all sites. The generally applied margin to cover uncertainties in range (3.5% of the prescribed range  +  1 mm) is not sufficient to cover the range uncertainty for ADC in all cases, especially for patients with high tissue heterogeneity. The root mean square of the R90 difference, the difference in the position of distal falloff to 90% of the prescribed dose, is affected by several factors, especially the patient geometry heterogeneity, modulation and field diameter. In conclusion, implementation of Monte Carlo dose calculation techniques into the clinic can reduce the uncertainty of the target dose for proton stereotactic radiosurgery. If MC is not available for treatment planning, using MC dose distributions to

  12. 2D vs. 3D mammography observer study

    NASA Astrophysics Data System (ADS)

    Fernandez, James Reza F.; Hovanessian-Larsen, Linda; Liu, Brent

    2011-03-01

    Breast cancer is the most common type of non-skin cancer in women. 2D mammography is a screening tool to aid in the early detection of breast cancer, but has diagnostic limitations of overlapping tissues, especially in dense breasts. 3D mammography has the potential to improve detection outcomes by increasing specificity, and a new 3D screening tool with a 3D display for mammography aims to improve performance and efficiency as compared to 2D mammography. An observer study using a mammography phantom was performed to compare traditional 2D mammography with this ne 3D mammography technique. In comparing 3D and 2D mammography there was no difference in calcification detection, and mass detection was better in 2D as compared to 3D. There was a significant decrease in reading time for masses, calcifications, and normals in 3D compared to 2D, however, as well as more favorable confidence levels in reading normal cases. Given the limitations of the mammography phantom used, however, a clearer picture in comparing 3D and 2D mammography may be better acquired with the incorporation of human studies in the future.

  13. MO-AB-207-04: ACR Update in Mammography

    SciTech Connect

    Berns, E.

    2015-06-15

    A goal of an imaging accreditation program is to ensure adequate image quality, verify appropriate staff qualifications, and to assure patient and personnel safety. Currently, more than 35,000 facilities in 10 modalities have been accredited by the American College of Radiology (ACR), making the ACR program one of the most prolific accreditation options in the U.S. In addition, ACR is one of the accepted accreditations required by some state laws, CMS/MIPPA insurance and others. Familiarity with the ACR accreditation process is therefore essential to clinical diagnostic medical physicists. Maintaining sufficient knowledge of the ACR program must include keeping up-to-date as the various modality requirements are refined to better serve the goals of the program and to accommodate newer technologies and practices. This session consists of presentations from authorities in four ACR accreditation modality programs, including magnetic resonance imaging, computed tomography, nuclear medicine, and mammography. Each speaker will discuss the general components of the modality program and address any recent changes to the requirements. Learning Objectives: To understand the requirements of the ACR MR Accreditation program. The discussion will include accreditation of whole-body general purpose magnets, dedicated extremity systems well as breast MRI accreditation. Anticipated updates to the ACR MRI Quality Control Manual will also be reviewed. To understand the requirements of the ACR CT accreditation program, including updates to the QC manual as well as updates through the FAQ process. To understand the requirements of the ACR nuclear medicine accreditation program, and the role of the physicist in annual equipment surveys and the set up and supervision of the routine QC program. To understand the current ACR MAP Accreditation requirement and present the concepts and structure of the forthcoming ACR Digital Mammography QC Manual and Program.

  14. 76 FR 60848 - National Mammography Quality Assurance Advisory Committee; Notice of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-30

    ... HUMAN SERVICES Food and Drug Administration National Mammography Quality Assurance Advisory Committee... be open to the public. Name of Committee: National Mammography Quality Assurance Advisory Committee...) Proposed changes to the Mammography Quality Standard Act (MQSA) policies and inspection procedures;...

  15. Mammography-oncogenecity at low doses.

    PubMed

    Heyes, G J; Mill, A J; Charles, M W

    2009-06-01

    Controversy exists regarding the biological effectiveness of low energy x-rays used for mammography breast screening. Recent radiobiology studies have provided compelling evidence that these low energy x-rays may be 4.42 +/- 2.02 times more effective in causing mutational damage than higher energy x-rays. These data include a study involving in vitro irradiation of a human cell line using a mammography x-ray source and a high energy source which matches the spectrum of radiation observed in survivors from the Hiroshima atomic bomb. Current radiation risk estimates rely heavily on data from the atomic bomb survivors, and a direct comparison between the diagnostic energies used in the UK breast screening programme and those used for risk estimates can now be made. Evidence highlighting the increase in relative biological effectiveness (RBE) of mammography x-rays to a range of x-ray energies implies that the risks of radiation-induced breast cancers for mammography x-rays are potentially underestimated by a factor of four. A pooled analysis of three measurements gives a maximal RBE (for malignant transformation of human cells in vitro) of 4.02 +/- 0.72 for 29 kVp (peak accelerating voltage) x-rays compared to high energy electrons and higher energy x-rays. For the majority of women in the UK NHS breast screening programme, it is shown that the benefit safely exceeds the risk of possible cancer induction even when this higher biological effectiveness factor is applied. The risk/benefit analysis, however, implies the need for caution for women screened under the age of 50, and particularly for those with a family history (and therefore a likely genetic susceptibility) of breast cancer. In vitro radiobiological data are generally acquired at high doses, and there are different extrapolation mechanisms to the low doses seen clinically. Recent low dose in vitro data have indicated a potential suppressive effect at very low dose rates and doses. Whilst mammography is a low

  16. Time perspective and perceived risk as related to mammography screening.

    PubMed

    Griva, Fay; Anagnostopoulos, Fotios; Potamianos, Gregory

    2013-01-01

    The present study explored the relation of time perspective to perceived risk for breast cancer and mammography screening. Women free from breast cancer (N = 194), eligible for mammography screening in terms of age, completed the Zimbardo Time Perspective Inventory (Zimbardo & Boyd, 1999) and measures of perceived risk, attitude toward performing mammography screening, intention to get a mammogram, and mammography screening behavior. Hierarchical multiple regression analysis revealed that perceived risk of breast cancer (β= .18, p < .01) and intention to be screened (β = .35, p < .01) were significantly associated with mammography screening, after controlling for the effects of sociodemographic (e.g., age, education, and economic level) and health-related variables (e.g., family history of breast cancer and previous benign breast disease). Path analyses including the main psychological variables indicated that perceived risk was indirectly related to intention via attitude (β = .17, p < .01), and to mammography screening through attitude and intention (β = .06, p < .01). Attitude was indirectly related to mammography screening via intention (β = .20, p < .01). Also, a significant indirect association was observed between future orientation and mammography screening, via perceived risk (β = .10, p < .01). Theoretical implications of study findings and suggestions for future research on use of mammography are presented.

  17. Diagnostic performance of radiologists with and without different CAD systems for mammography

    NASA Astrophysics Data System (ADS)

    Lauria, Adele; Fantacci, Maria E.; Bottigli, Ubaldo; Delogu, Pasquale; Fauci, Francesco; Golosio, Bruno; Indovina, Pietro L.; Masala, Giovanni L.; Oliva, Piernicola; Palmiero, Rosa; Raso, Giuseppe; Stumbo, Simone; Tangaro, Sabina

    2003-05-01

    The purpose of this study is the evaluation of the variation of performance in terms of sensitivity and specificity of two radiologists with different experience in mammography, with and without the assistance of two different CAD systems. The CAD considered are SecondLookTM (CADx Medical Systems, Canada), and CALMA (Computer Assisted Library in MAmmography). The first is a commercial system, the other is the result of a research project, supported by INFN (Istituto Nazionale di Fisica Nucleare, Italy); their characteristics have already been reported in literature. To compare the results with and without these tools, a dataset composed by 70 images of patients with cancer (biopsy proven) and 120 images of healthy breasts (with a three years follow up) has been collected. All the images have been digitized and analysed by two CAD, then two radiologists with respectively 6 and 2 years of experience in mammography indipendently made their diagnosis without and with, the support of the two CAD systems. In this work sensitivity and specificity variation, the Az area under the ROC curve, are reported. The results show that the use of a CAD allows for a substantial increment in sensitivity and a less pronounced decrement in specificity. The extent of these effects depends on the experience of the readers and is comparable for the two CAD considered.

  18. Feasibility study for positron emission mammography.

    PubMed

    Thompson, C J; Murthy, K; Weinberg, I N; Mako, F

    1994-04-01

    A feasibility study is presented for a small, low-cost, dedicated device for positron emission mammography. Two detector arrays above and below the breast would be placed in a conventional mammography unit. These detectors are sensitive to positron annihilation radiation, and are connected to a coincidence circuit and a multiplane image memory. Images of the distribution of positron-emitting isotope are obtained in real time by incrementing the memory location at the intersection of each line of response. Monte Carlo simulations of a breast phantom are compared with actual scans of this phantom in a conventional PET scanner. The simulations and experimental data are used to predict the performance of the proposed system. Spatial resolution experiments using very narrow bismuth germanate BGO crystals suggest that spatial resolutions of about 2 mm should be possible. The efficiency of the proposed device is about ten times that of a conventional brain scanner. The scatter fraction is greater, but the scattered radiation has a very flat distribution. By designing the device to fit in an existing mammography unit, conventional mammograms can be taken after the injection of the radio-pharmaceutical allowing exact registration of the emission and conventional mammographic images.

  19. Technology assessment: observer study directly compares screen/film to CR mammography

    NASA Astrophysics Data System (ADS)

    Fletcher-Heath, Lynn; Richards, Anne; Ryan-Kron, Susan

    2007-03-01

    A new study supports and expands upon a previous reporting that computed radiography (CR) mammography offers as good, or better, image quality than state-of-the-art screen/film mammography. The suitability of CR mammography is explored through qualitative and quantitative study components: feature comparison and cancer detection rates of each modality. Images were collected from 150 normal and 50 biopsy-confirmed subjects representing a range of breast and pathology types. Comparison views were collected without releasing compression, using automatic exposure control on Kodak MIN-R films, followed by CR. Digital images were displayed as both softcopy (S/C) and hardcopy (H/C) for the feature comparison, and S/C for the cancer detection task. The qualitative assessment used preference scores from five board-certified radiologists obtained while viewing 100 screen/film-CR pairs from the cancer subjects for S/C and H/C CR output. Fifteen general image-quality features were rated, and up to 12 additional features were rated for each pair, based on the pathology present. Results demonstrate that CR is equivalent or preferred to conventional mammography for overall image quality (89% S/C, 95% H/C), image contrast (95% S/C, 98% H/C), sharpness (86% S/C, 93% H/C), and noise (94% S/C, 91% H/C). The quantitative objective was satisfied by asking 10 board-certified radiologists to provide a BI-RADS TM score and probability of malignancy per breast for each modality of the 200 cases. At least 28 days passed between observations of the same case. Average sensitivity and specificity was 0.89 and 0.82 for CR and 0.91 and 0.82 for screen/film, respectively.

  20. Screening Mammography Utilization in Tennessee Women: The Association with Residence

    ERIC Educational Resources Information Center

    Brown, Kathleen C.; Fitzhugh, Eugene C.; Neutens, James J.; Klein, Diane A.

    2009-01-01

    Context: Approximately 70% of US women over age 40 report mammography screening within 2 years. However, rates are likely to vary by age, income, educational level, and residence. Purpose: To describe the prevalence of screening mammography and associated factors in women living in rural and urban areas of Tennessee. Methods: Using pooled data…

  1. Reproducibility of Mammography Units, Film Processing and Quality Imaging

    NASA Astrophysics Data System (ADS)

    Gaona, Enrique

    2003-09-01

    The purpose of this study was to carry out an exploratory survey of the problems of quality control in mammography and processors units as a diagnosis of the current situation of mammography facilities. Measurements of reproducibility, optical density, optical difference and gamma index are included. Breast cancer is the most frequently diagnosed cancer and is the second leading cause of cancer death among women in the Mexican Republic. Mammography is a radiographic examination specially designed for detecting breast pathology. We found that the problems of reproducibility of AEC are smaller than the problems of processors units because almost all processors fall outside of the acceptable variation limits and they can affect the mammography quality image and the dose to breast. Only four mammography units agree with the minimum score established by ACR and FDA for the phantom image.

  2. Development of a High Resolution Digital Mammography System.

    DTIC Science & Technology

    1995-09-12

    coefficients", US Dept. of Commerce, NISTIR 89-4144 (1989) [29] G. Rakavy, A. Ron, "Atomic Photoeffect in the Range Ey = 1-2000 keV", Physical Review, Vol. 159...Report: Zhenxue Jing [36] T.R. Fewell, R.E. Shuping, Handbook of Mammographic X-ray Spectra, DHBEW Publ. (FDA) 79- 8071 (U.S. GPO, Washington, D.C

  3. Simulation, Measurements and Image Processing for Capillary Optical Digital Mammography

    DTIC Science & Technology

    2000-07-01

    authors wish to acknowledge assistance from Michael Gubarev, Frank Hoffman, Christine Russel, C.A. Freinberg- Trufas , Francisca Sugiro and Sushil Padiyar...Christine Russell , C.A. Freinberg- Trufas , Francisca Sugiro and Sushil Padiyar. The Department of Army Breast Cancer Research Project grant DAMD 17-97-1-7304

  4. Advanced Signal Processing Methods Applied to Digital Mammography

    NASA Technical Reports Server (NTRS)

    Stauduhar, Richard P.

    1997-01-01

    The work reported here is on the extension of the earlier proposal of the same title, August 1994-June 1996. The report for that work is also being submitted. The work reported there forms the foundation for this work from January 1997 to September 1997. After the earlier work was completed there were a few items that needed to be completed prior to submission of a new and more comprehensive proposal for further research. Those tasks have been completed and two new proposals have been submitted, one to NASA, and one to Health & Human Services WS). The main purpose of this extension was to refine some of the techniques that lead to automatic large scale evaluation of full mammograms. Progress on each of the proposed tasks follows. Task 1: A multiresolution segmentation of background from breast has been developed and tested. The method is based on the different noise characteristics of the two different fields. The breast field has more power in the lower octaves and the off-breast field behaves similar to a wideband process, where more power is in the high frequency octaves. After the two fields are separated by lowpass filtering, a region labeling routine is used to find the largest contiguous region, the breast. Task 2: A wavelet expansion that can decompose the image without zero padding has been developed. The method preserves all properties of the power-of-two wavelet transform and does not add appreciably to computation time or storage. This work is essential for analysis of the full mammogram, as opposed to selecting sections from the full mammogram. Task 3: A clustering method has been developed based on a simple counting mechanism. No ROC analysis has been performed (and was not proposed), so we cannot finally evaluate this work without further support. Task 4: Further testing of the filter reveals that different wavelet bases do yield slightly different qualitative results. We cannot provide quantitative conclusions about this for all possible bases without further support. Task 5: Better modeling does indeed make an improvement in the detection output. After the proposal ended, we came up with some new theoretical explanations that helps in understanding when the D4 filter should be better. This work is currently in the review process. Task 6: N/A. This no longer applies in view of Tasks 4-5. Task 7: Comprehensive plans for further work have been completed. These plans are the subject of two proposals, one to NASA and one to HHS. These proposals represent plans for a complete evaluation of the methods for identifying normal mammograms, augmented with significant further theoretical work.

  5. Organic Polymer Light Emitting Display for Digital Mammography

    DTIC Science & Technology

    2003-03-01

    displays (AM-OLEDs) based on a three hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) pixel electrode circuit that supplies a continuous...can prevent the development of the high-resolution displays. Also so far all AM-OLEDs are based on poly-crystalline silicon (poly- Si) TFT technology... PEDOT ) doped with poly(styrenesulfonate) (PSS) and green light-emitting poly (fluorene) copolymer were used for HIL and LEL materials, respectively

  6. Adaptive Computer-Assisted Mammography Training for Improved Breast Cancer Screening

    DTIC Science & Technology

    2012-10-01

    11-1-0755 TITLE: Adaptive Computer-Assisted Mammography Training for Improved Breast Cancer Screening PRINCIPAL INVESTIGATOR: Maciej...AND SUBTITLE 5a. CONTRACT NUMBER Adaptive Computer-Assisted Mammography Training for Improved Breast Cancer Screening 5b. GRANT...propose to research the methodology for constructing adaptive computer-aided education systems for mammography . Improved mammography education could

  7. Mammography Screening – as of 2013

    PubMed Central

    Heywang-Koebrunner, S.; Bock, K.; Heindel, W.; Hecht, G.; Regitz-Jedermann, L.; Hacker, A.; Kaeaeb-Sanyal, V.

    2013-01-01

    Introduction: Since 2008 the German Mammography Screening Programme has been available throughout Germany to all women aged between 50 and 69. The programme strictly follows the European Guidelines. There are controversial discussions in the media as well as in the specialised press. Materials and Methods: Overview of the available data with regard to an evaluation of randomised studies and with regard to quality-assured screening programmes in accordance with EU Guidelines (including data from 18 screening countries). Results: Positive effects of screening: reduction in mortality, less invasive treatment. Negative effects: False-positive diagnoses and biopsy recommendations, so-called overdiagnoses, radiation dose. Limits of screening: Interval carcinomas, incomplete reduction in mortality. A mathematical synopsis of the latest publications from the European screening programmes with the diagnosis rates in Germany determined from > 4.6 million screening examinations produces the following: a total of 10 000 mammograms are created for 1000 women (P) taking part in the Mammography Screening Programme (each of whom undergoes 10 mammograms in 20 years). Overall, the risk of triggering breast cancer through a mammogram is very clearly below the annual natural risk of suffering from breast cancer. In the German screening, of these 1000 women, an average of 288 women are called back once in 20 years as a result of changes that are ultimately benign (< 3 % per cycle). Of these, 74 of the 288 women undergo a biopsy due to a benign change (false-positive biopsy recommendations, usually punch or vacuum biopsies). According to EUROSCREEN, 71 carcinomas develop among participants (56 are discovered in the screening, 15 in the interval), and 67 carcinomas among non-participants (N-P) (in some cases, several years later) during this period. The 4 additional diagnoses among the Ps are referred to as overdiagnoses, as they do not contribute to a reduction in mortality

  8. Adaptive Computer-Assisted Mammography Training for Improved Breast Cancer Screening

    DTIC Science & Technology

    2014-10-01

    education could lead to improved benefit of mammography to breast cancer care and in turn to decreased mortality from the disease. The project...models. The proposed adaptive system could improve education in mammography. This may in turn result in improved benefit of mammography in breast cancer ...adaptive system could improve education in mammography. This may in turn result in improved benefit of mammography in breast cancer detection and lower

  9. Preliminary experience with monoenergetic photon mammography

    SciTech Connect

    Johnston, R.E.; Washburn, D.; Pisano, E.; Thomlinson, W.C.; Chapman, D.; Gmur, N.F.; Zhong, Zhong; Sayers, D.

    1995-12-31

    We are using a beam port at the National Synchrotron Light Source facility at Brookhaven National Laboratory as a source of monoenergetic photons. The photon source is radiation from a bending magnet on the X-ray storage ring and provides a usable X-ray spectrum from 5 keV to over 50 keV. A tunable crystal monochromotor is used for energy selection. The beam is 79mm wide and 0.5 mm high. We imaged the ACR mammography phantom and a contrast-detail phantom using a phosphor plate as the unaging detector. Phantom images were obtained at 16, 18, 20 and 22 keV. Phantom thickness varied from 15 mm to 82 mm. These images were compared to images obtained with a conventional dedicated mammography unit. Subjective preliminary results show that image contrast of the monoenergetic images is similar to those obtained from the conventional x-ray source with somewhat sharper and cleaner images from the monoenergetic source. Quantitative analysis shows that the monoenergetic images have improved contrast compared to the polyenergetic derived images. Entrance skin dose measurements show a factor of 5 to 10 times less radiation for the monoenergetic images with equivalent or better contrast Although there remain a number of technical problems to be addressed and much more work to be done, we are encouraged to further explore the use of monoenergetic imaging.

  10. Mammography screening among the elderly: A research challenge

    PubMed Central

    Sanderson, Maureen; Levine, Robert S.; Fadden, Mary K.; Kilbourne, Barbara; Pisu, Maria; Cain, Van; Husaini, Baqar A.; Langston, Michael; Gittner, Lisa; Zoorob, Roger; Rust, George S.; Hennekens, Charles H.

    2015-01-01

    Background Randomized trials demonstrate clear benefits of mammography screening in women through age 74 years. We explored age- and race-specific rates of mammography screening and breast cancer mortality among women ages 69 to 84 years. Methods We analyzed Medicare claims data for women residing within Surveillance, Epidemiology and End Results (SEER) geographic areas from 1995 to 2009 from 64,384 non-Hispanic women (4,886 black and 59,498 white) and ascertained all primary breast cancer cases diagnosed between ages 69 and 84 years. The exposure was annual or biennial screening mammography during the four years immediately preceding diagnosis. The outcome was breast cancer mortality during the ten years immediately following diagnosis. Results After adjustment for stage at diagnosis, radiation therapy, chemotherapy, co-morbid conditions and contextual socio-economic status, hazard ratios (HR’s) (and 95% confidence intervals) for breast cancer mortality relative to no/irregular mammography at 10 years for women ages 69–84 years at diagnosis were 0.31 (0.29–0.33) for annual and 0.47 (0.44–0.51) for biennial mammography among whites and 0.36 (0.29–0.44) for annual and 0.47 (0.37–0.58) for biennial mammography among blacks. Trends were similar at five years overall as well as stratified by ages 69–74, 75–78, and 79–84. Conclusions In these Medicare claims and SEER data, elderly non-Hispanic women who self-selected for annual mammography had lower ten-year breast cancer mortality than corresponding women who self-selected for either biennial or no/irregular mammography. These findings were similar among black and white women. The data highlight the evidentiary limitations of data used for current screening mammography recommendations. PMID:26169884

  11. An assessment of American Indian women's mammography experiences

    PubMed Central

    2010-01-01

    Background Mortality from breast cancer has increased among American Indian/Alaskan Native (AI/AN) women. Despite this alarming reality, AI/AN women have some of the lowest breast cancer screening rates. Only 37% of eligible AI/AN women report a mammogram within the last year and 52% report a mammogram within the last two years compared to 57% and 72% for White women. The experiences and satisfaction surrounding mammography for AI/AN women likely are different from that of women of other racial/ethnic groups, due to cultural differences and limited access to Indian Health Service sponsored mammography units. The overall goals of this study are to identify and understand the mammography experiences and experiential elements that relate to satisfaction or dissatisfaction with mammography services in an AI/AN population and to develop a culturally-tailored AI/AN mammography satisfaction survey. Methods and Design The three project aims that will be used to guide this work are: 1) To compare the mammography experiences and satisfaction with mammography services of Native American/Alaska Native women with that of Non-Hispanic White, Hispanic, and Black women, 2) To develop and validate the psychometric properties of an American Indian Mammography Survey, and 3) To assess variation among AI/AN women's assessments of their mammography experiences and mammography service satisfaction. Evaluations of racial/ethnic differences in mammography patient satisfaction have received little study, particularly among AI/AN women. As such, qualitative study is uniquely suited for an initial examination of their experiences because it will allow for a rich and in-depth identification and exploration of satisfaction elements. Discussion This formative research is an essential step in the development of a validated and culturally tailored AI/AN mammography satisfaction assessment. Results from this project will provide a springboard from which a maximally effective breast cancer

  12. Problems, solutions, and perspectives in the evaluation of interval cancers in Italian mammography screening programmes: a position paper from the Italian group for mammography screening (GISMa).

    PubMed

    Bucchi, Lauro; Frigerio, Alfonso; Zorzi, Manuel; Fedato, Chiara; Angiolucci, Giovanni; Bernardi, Daniela; Campari, Cinzia; Crocetti, Emanuele; Ferretti, Stefano; Giorgi, Daniela; Marchisio, Francesca; Morrone, Doralba; Naldoni, Carlo; Petrella, Marco; Ponti, Antonio; Ravaioli, Alessandra; Saguatti, Gianni; Santini, Dolores; Sassoli de Bianchi, Priscilla; Serafini, Monica; Vergini, Viviana; Giordano, Livia

    2015-01-01

    , finally, analysis could be restricted to the absolute incidence rate of IBC, which would make comparison of the risk between neighbouring populations possible. Epidemiologists must extend their attention to the prevention of the risk of IBC and the implementation of breast radiology quality assurance practices. Epidemiologists and radiologists can share common objectives: it is necessary to promote the idea that the availability of a registry-based series of IBCs is not a prerequisite for their radiological review; radiological review of breast cancers greater than 20mm in size detected at second and subsequent screens, that are potential substitutes for IBCs, needs radiological and epidemiological validation studies; the advent of digital mammography brings about the possibility to create libraries of mammograms accessible online, which enables the conduct of large studies of the diagnostic variability of radiologists; and, finally, epidemiologists and radiologists have the responsibility to monitor the effects that a loss of cumulative professional experience in screening centres, due to the imminent retirement of a substantial proportion of healthcare workforce, could cause on their performance.

  13. Evaluation of Doses and Image Quality in Mammography with Screen-Film, CR, and DR Detectors – Application of the ACR Phantom

    PubMed Central

    Ślusarczyk-Kacprzyk, Wioletta; Skrzyński, Witold; Fabiszewska, Ewa

    2016-01-01

    Summary Background Different methods of image quality evaluation are routinely used for analogue and digital mammography systems in Poland. In the present study, image quality for several screen-film (SF), computed radiography (CR), and fully digital (DR) mammography systems was compared directly with the use of the ACR mammography accreditation phantom. Material/Methods Image quality and mean glandular doses were measured and compared for 47 mammography systems in the Mazovia Voivodeship in Poland, including 26 SF systems, 12 CR systems, and 9 DR systems. The mean glandular dose for the breast simulated by 4.5 cm of PMMA was calculated with methods described in the “European guidelines for quality assurance in breast cancer screening and diagnosis”. Visibility of the structures in the image (fibers, microcalcifications, and masses) was evaluated with the mammographic accreditation ACR phantom. Results Image quality for DR systems was significantly higher than for SF and CR systems. Several SF systems failed to pass the image quality tests because of artifacts. The doses were within acceptable limits for all of the systems, but the doses for the CR systems were significantly higher than for the SF and DR systems. Conclusions The best image quality, at a reasonably low dose, was observed for the DR systems. The CR systems are capable of obtaining the same image quality as the SF systems, but only at a significantly higher dose. The ACR phantom can be routinely used to evaluate image quality for all types of mammographic systems. PMID:27617048

  14. Determinants of the number of mammography units in 31 countries with significant mammography screening

    PubMed Central

    Autier, P; Ouakrim, D A

    2008-01-01

    In the 2000s, most of the female population of industrialised countries had access to mammography breast cancer screening, but with variable modalities among the countries. We assessed the number of mammography units (MUs) in 31 European, North American and Asian countries where significant mammography activity has existed for over 10 years, collecting data on the number of such units and of radiologists by contacting institutions in each country likely to provide the relevant information. Around 2004, there were 32 324 MU in 31 countries, the number per million women ranging from less than 25 in Turkey, Denmark, the Netherlands, the United Kingdom, Norway, Poland and Hungary to more than 80 in Cyprus, Italy, France, the United States and Austria. In a multivariate analysis, the number of MUs was positively associated with the number of radiologists (P=0.0081), the number of women (P=0.0023) and somewhat with the country surface area (P=0.077). There is considerable variation in the density of MU across countries and the number of MUs in service are often well above what would be necessary according to local screening recommendations. High number of MUs in some countries may have undesirable consequences, such as unnecessarily high screening frequency and decreased age at which screening is started. PMID:18781176

  15. A proposal for a national mammography database: content, purpose, and value.

    PubMed

    Osuch, J R; Anthony, M; Bassett, L W; DeBor, M; D'Orsi, C; Hendrick, R E; Linver, M; Smith, R

    1995-06-01

    A national mammography database is a centralized, computerized method of data collection consisting of two possible parts: a national mammography audit and a system for monitoring and tracking patients. A national mammography audit refers to collecting and analyzing medical audit data of individual mammography practices at a national level and is a critical step in improving the interpretive component of mammography. The monitoring and tracking component refers to a centralized system that provides women and physicians with a recruitment and follow-up mechanism to optimize participation in mammography services. Both parts of a national mammography database represent important components in the improvement of mammography quality. However, unique scientific, legal, and fiscal concerns are important to consider before establishing a national mammography database.

  16. Influence of advertisement on women's attitudes toward mammography screening.

    PubMed

    Collins, C; Davis, L S; Rentz, K; Vannoy, D

    1997-01-01

    This project represents an effort to incorporate a feminist perspective into research on mammography screening. The purpose of this study was to assess women's attitudes toward four advertisements designed to encourage mammography screening. The goal was to create awareness about women's attitudes toward mammography advertisements in order to encourage the development of more effective and responsive motivational materials. The results indicated that each ad communicated different messages about the seriousness of breast cancer and the efficacy of mammography in detecting early breast cancer. Each ad also affected women differently regarding their feelings of control over breast cancer, their perceived loss of sex appeal resulting from a breast cancer diagnosis, and their general fear of breast cancer.

  17. Elasto-mammography: Theory, Algorithm, and Phantom Study

    PubMed Central

    Liu, Y.; Sun, L. Z.; Wang, G.; Fajardo, L. L.

    2006-01-01

    A new imaging modality framework, called elasto-mammography, is proposed to generate the elastograms of breast tissues based on conventional X-ray mammography. The displacement information is extracted from mammography projections before and after breast compression. Incorporating the displacement measurement, an elastography reconstruction algorithm is specifically developed to estimate the elastic moduli of heterogeneous breast tissues. Case studies with numerical breast phantoms are conducted to demonstrate the capability of the proposed elasto-mammography. Effects of noise with measurement, geometric mismatch, and elastic contrast ratio are evaluated in the numerical simulations. It is shown that the proposed methodology is stable and robust for characterization of the elastic moduli of breast tissues from the projective displacement measurement. PMID:23165036

  18. A Novel Method to Assess Incompleteness of Mammography Reports

    PubMed Central

    Gimenez, Francisco J.; Wu, Yirong; Burnside, Elizabeth S.; Rubin, Daniel L.

    2014-01-01

    Mammography has been shown to improve outcomes of women with breast cancer, but it is subject to inter-reader variability. One well-documented source of such variability is in the content of mammography reports. The mammography report is of crucial importance, since it documents the radiologist’s imaging observations, interpretation of those observations in terms of likelihood of malignancy, and suggested patient management. In this paper, we define an incompleteness score to measure how incomplete the information content is in the mammography report and provide an algorithm to calculate this metric. We then show that the incompleteness score can be used to predict errors in interpretation. This method has 82.6% accuracy at predicting errors in interpretation and can possibly reduce total diagnostic errors by up to 21.7%. Such a method can easily be modified to suit other domains that depend on quality reporting. PMID:25954448

  19. A novel method to assess incompleteness of mammography reports.

    PubMed

    Gimenez, Francisco J; Wu, Yirong; Burnside, Elizabeth S; Rubin, Daniel L

    2014-01-01

    Mammography has been shown to improve outcomes of women with breast cancer, but it is subject to inter-reader variability. One well-documented source of such variability is in the content of mammography reports. The mammography report is of crucial importance, since it documents the radiologist's imaging observations, interpretation of those observations in terms of likelihood of malignancy, and suggested patient management. In this paper, we define an incompleteness score to measure how incomplete the information content is in the mammography report and provide an algorithm to calculate this metric. We then show that the incompleteness score can be used to predict errors in interpretation. This method has 82.6% accuracy at predicting errors in interpretation and can possibly reduce total diagnostic errors by up to 21.7%. Such a method can easily be modified to suit other domains that depend on quality reporting.

  20. Dual-energy contrast-enhanced spectral mammography (CESM).

    PubMed

    Daniaux, Martin; De Zordo, Tobias; Santner, Wolfram; Amort, Birgit; Koppelstätter, Florian; Jaschke, Werner; Dromain, Clarisse; Oberaigner, Willi; Hubalek, Michael; Marth, Christian

    2015-10-01

    Dual-energy contrast-enhanced mammography is one of the latest developments in breast care. Imaging with contrast agents in breast cancer was already known from previous magnetic resonance imaging and computed tomography studies. However, high costs, limited availability-or high radiation dose-led to the development of contrast-enhanced spectral mammography (CESM). We reviewed the current literature, present our experience, discuss the advantages and drawbacks of CESM and look at the future of this innovative technique.

  1. X-ray source for mammography

    DOEpatents

    Logan, Clinton M.

    1994-01-01

    An x-ray source utilizing anode material which shifts the output spectrum to higher energy and thereby obtains higher penetrating ability for screening mammography application, than the currently utilized anode material. The currently used anode material (molybdenum) produces an energy x-ray spectrum of 17.5/19.6 keV, which using the anode material of this invention (e.g. silver, rhodium, and tungsten) the x-ray spectrum would be in the 20-35 keV region. Thus, the anode material of this invention provides for imaging of breasts with higher than average x-ray opacity without increase of the radiation dose, and thus reduces the risk of induced breast cancer due to the radiation dose administered for mammograms.

  2. X-ray source for mammography

    DOEpatents

    Logan, C.M.

    1994-12-20

    An x-ray source is described utilizing anode material which shifts the output spectrum to higher energy and thereby obtains higher penetrating ability for screening mammography application, than the currently utilized anode material. The currently used anode material (molybdenum) produces an energy x-ray spectrum of 17.5/19.6 keV, which using the anode material of this invention (e.g. silver, rhodium, and tungsten) the x-ray spectrum would be in the 20-35 keV region. Thus, the anode material of this invention provides for imaging of breasts with higher than average x-ray opacity without increase of the radiation dose, and thus reduces the risk of induced breast cancer due to the radiation dose administered for mammograms. 6 figures.

  3. Instrumentation optimization for positron emission mammography

    SciTech Connect

    Moses, William W.; Qi, Jinyi

    2003-06-05

    The past several years have seen designs for PET cameras optimized to image the breast, commonly known as Positron Emission Mammography or PEM cameras. The guiding principal behind PEM instrumentation is that a camera whose field of view is restricted to a single breast has higher performance and lower cost than a conventional PET camera. The most common geometry is a pair of parallel planes of detector modules, although geometries that encircle the breast have also been proposed. The ability of the detector modules to measure the depth of interaction (DOI) is also a relevant feature. This paper finds that while both the additional solid angle coverage afforded by encircling the breast and the decreased blurring afforded by the DOI measurement improve performance, the ability to measure DOI is more important than the ability to encircle the breast.

  4. Development of a trans-admittance mammography (TAM) using 60×60 electrode array

    NASA Astrophysics Data System (ADS)

    Zhao, Mingkang; Liu, Qin; In Oh, Tong; Woo, Eung Je; Seo, Jin Keun

    2010-04-01

    We have developed a trans-admittance mammography (TAM) system as a supplementary or alternative method of the X-ray mammography to diagnose the breast cancer. Mechanical structure of the system is similar to the X-ray mammography with the breast placed between two plates. The pair of plates is movable to accommodate breasts with different sizes and rotatable to provide multiple images with different projection angles. Without using ionizing radiation, it acquires a projection image of tissue admittivity values. One plate is a flat solid electrode where we apply a constant sinusoidal voltage with a variable frequency. The other is equipped with 60×60 array of current-sensing electrodes, of which potentials are kept at the signal reference level. The electrode array is connected to six switching modules and each module routes current signals from 600 electrodes to two ammeter modules. Each ammeter module includes six channels of ammeters and each one of them comprises an independent current-to-voltage converter, voltage amplifier, ADC and digital phase-sensitive demodulator. Each ammeter sequentially measures exit currents from 50 electrodes chosen by the corresponding switching module. An FPGA controls six ammeters to collect real- and imaginary-parts of trans-admittance data from 300 electrodes. A separate FPGA arbitrates data and command exchanges between a DSP-based main controller and ammeter modules. It also generates a sinusoidal voltage signal to be applied to the breast. All the 3600 complex current data from 12 ammeter modules are transferred to the main controller, which is interfaced to a PC through an isolated USB. The system is provided with a program to display real- and imaginary-parts of measured trans-admittance maps. The measured maps at multiple frequencies are incorporated into a frequency-difference anomaly detection algorithm. In this paper, we describe the design and construction of the system.

  5. Association Between Time Spent Interpreting, Level of Confidence and Accuracy of Screening Mammography

    PubMed Central

    Carney, Patricia A.; Bogart, Andy; Geller, Berta M.; Haneuse, Sebastian; Kerlikowske, Karla; Buist, Diana SM; Smith, Robert; Rosenberg, Robert; Yankaskas, Bonnie C.; Onega, Tracy; Miglioretti, Diana L.

    2013-01-01

    Purpose To examine the effect of time spent viewing images and level of confidence on a screening mammography test set on interpretive performance. Materials and Methods Radiologists from six mammography registries participated in the study and were randomized to interpret one of four test sets and complete 12 survey questions. Each test set had 109 cases of digitized four-view screening film-screen mammograms with prior comparison screening views. Viewing time for each case was defined as the cumulative time spent viewing all mammographic images before recording which visible feature, if any, was the “most significant finding”. Log-linear regression fit via GEE was used to test the effect of viewing time and level of confidence in the interpretation on test set sensitivity and false-positive rate. Results 119 radiologists completed a test set and contributed data on 11,484 interpretations. Radiologists spent more time viewing cases that had significant findings or for which they had less confidence in interpretation. Each additional minute of viewing time increased the probability of a true positive interpretation among cancer cases by 1.12 (95% CI: 1.06, 1.19, p<0.001), regardless of confidence in the assessment. Among radiologists who were ‘very confident’ in their assessment, each additional minute of viewing time increased the adjusted risk of a false positive interpretation among non-cancer cases by 1.42 (95% CI 1.21, 1.68), and this viewing-time effect diminished with decreasing confidence. Conclusions Longer interpretation times and higher levels of confidence in the interpretation are both associated with higher sensitivity and false positive rates in mammography screening. PMID:22451568

  6. Evaluation of detectors for the small field measurements used for clinical radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Markovic, Miljenko

    Advanced radiation therapy treatments with very small field sizes are complex. Increasingly higher doses delivered in single or few fractions are being commonly used for the treatments of the small target volume. Absolute or relative small field dosimetry is difficult due to radiation transport. Therefore it is very important to understand characteristics of the small field, detector selection as well as correction factors that have to be taken into account for the accurate measurements. Reducing uncertainty in relative dose measurement and modeling dose on treatment planning systems are factors contributing to the accuracy of the small field radiation treatments. Several challenges in small field dosimetry arise because of the lack of lateral charge particle equilibrium as well as the occlusion of the direct photon beam source and collimator settings. Presence of low-density media in irradiation geometry does complicate dosimetry even more. All those conditions are representing the challenge when it comes to dosimetric measurements. Size and construction are crucial when it comes to choice of the detector. Depending on beam energy, resolving the beam profile and penumbra for the small field sizes are a challenge and practically impossible with detectors commonly used in clinics. With decreasing field size and due to changes in particle spectrum, variations in radiological parameters have to be taken into account. To measure percent depth dose, tissue maximum ratios, tissue phantom ratios as well as output factors for the small field size experimental studies and Monte Carlo simulations have been conducted to determine appropriate detectors for the measurements. The primary goal of Specific Aim 1 was experimental quantification of the performance parameters for single detectors used for dosimetric verification of the small fields in radiotherapy. The proposed method and qualitative value for appropriate detectors selection defined by field size has been set. The

  7. Identification, segmentation, and characterization of microcalcifications on mammography

    NASA Astrophysics Data System (ADS)

    Drukker, Karen; Malkov, Serghei; Avila, Jesus; Kerlikowske, Karla; Joe, Bonnie; Krings, Gregor; Creasman, Jennifer; Drukteinis, Jennifer S.; Pereira, Malesa M.; Kazemi, Leila; Shepherd, John; Giger, Maryellen

    2016-03-01

    The purpose was to develop a characterization method for breast lesions visible only as microcalcifications on digital mammography. The method involved 4 steps: 1) image preprocessing through morphological filtering, 2) un-supervised identification of microcalcifications in the region surrounding the radiologist-indicated location through k-means clustering, 3) segmentation of the identified microcalcifications using an active contour model, and 4) characterization by computer-extracted image-based phenotypes describing properties of individual microcalcifications, cluster, and surrounding parenchyma. The image-based phenotypes were investigated for their ability to distinguish - individually, i.e., without merging with other phenotypes with a classifier - between invasive breast cancers, in-situ (non-invasive) breast cancers, fibroadenomas, and other benign-type lesions. The data set contained diagnostic mammograms of 82 patients with 2 views per patient - cranio-caudal (CC) and medio-lateral (ML) views of the affected breast with a single biopsy-proven finding indicated per view - with 7 invasive cancers, 14 in situ cancers, 13 fibroadenomas, and 48 other benign-type lesions. Analysis was performed per lesion and calculated phenotypes were averaged over views. Performance was assessed using ROC analysis with individual phenotypes as decision variables in the tasks of a) pairwise distinction amongst the 4 finding types, b) distinction between each finding type and all others, and c) distinction between cancer and non-cancer. Different phenotypes emerged as the best performers with areas under the ROC curve ranging from 0.69 (0.05) to 0.92 (0.09) depending on the task. We obtained encouraging preliminary results beyond the classification of cancer versus non-cancer in the distinction between different types of breast lesions visible as mammographic calcifications.

  8. Precise calibration of CCD images with a small field of view. Application to observations of Phoebe

    NASA Astrophysics Data System (ADS)

    Peng, Q.; Vienne, A.; Han, Y. B.; Li, Z. L.

    2004-09-01

    A precise astrometric calibration method is presented for a CCD image with a small field of view. Its detailed computational formulae are given, and its feasibility and accuracy are tested by the observations of both the star and Phoebe, the 9th satellite of Saturn. This new method can also be applicable to other planetary satellites, asteroids and optical counterparts of extragalactic radio sources.

  9. Radiation protection program for early detection of breast cancer in a mammography facility

    NASA Astrophysics Data System (ADS)

    Villagomez Casimiro, Mariana; Ruiz Trejo, Cesar; Espejo Fonseca, Ruby

    2014-11-01

    Mammography is the best tool for early detection of Breast Cancer. In this diagnostic radiology modality it is necessary to establish the criteria to ensure the proper use and operation of the equipment used to obtain mammographic images in order to contribute to the safe use of ionizing radiation. The aim of the work was to implement at FUCAM-AC the radiation protection program which must be established for patients and radiation workers according to Mexican standards [1-4]. To achieve this goal, radiation protection and quality control manuals were elaborated [5]. Furthermore, a quality control program (QCP) in the mammography systems (analog/digital), darkroom included, has been implemented. Daily sensitometry, non-variability of the image quality, visualizing artifacts, revision of the equipment mechanical stability, compression force and analysis of repetition studies are some of the QCP routine tests that must be performed by radiological technicians of this institution as a set of actions to ensure the protection of patients. Image quality and patients dose assessment were performed on 4 analog equipment installed in 2 mobile units. In relation to dose assessment, all equipment passed the acceptance criteria (<3 mGy per projection). The image quality test showed that most images (70%)- presented artifacts. A brief summary of the results of quality control tests applied to the equipment and film processor are presented. To maintain an adequate level of quality and safety at FUCAM-AC is necessary that the proposed radiation protection program in this work is applied.

  10. Radiation protection program for early detection of breast cancer in a mammography facility

    SciTech Connect

    Mariana, Villagomez Casimiro E-mail: cesar@fisica.unam.mx; Cesar, Ruiz Trejo E-mail: cesar@fisica.unam.mx; Ruby, Espejo Fonseca

    2014-11-07

    Mammography is the best tool for early detection of Breast Cancer. In this diagnostic radiology modality it is necessary to establish the criteria to ensure the proper use and operation of the equipment used to obtain mammographic images in order to contribute to the safe use of ionizing radiation. The aim of the work was to implement at FUCAM-AC the radiation protection program which must be established for patients and radiation workers according to Mexican standards [1–4]. To achieve this goal, radiation protection and quality control manuals were elaborated [5]. Furthermore, a quality control program (QCP) in the mammography systems (analog/digital), darkroom included, has been implemented. Daily sensitometry, non-variability of the image quality, visualizing artifacts, revision of the equipment mechanical stability, compression force and analysis of repetition studies are some of the QCP routine tests that must be performed by radiological technicians of this institution as a set of actions to ensure the protection of patients. Image quality and patients dose assessment were performed on 4 analog equipment installed in 2 mobile units. In relation to dose assessment, all equipment passed the acceptance criteria (<3 mGy per projection). The image quality test showed that most images (70%)– presented artifacts. A brief summary of the results of quality control tests applied to the equipment and film processor are presented. To maintain an adequate level of quality and safety at FUCAM-AC is necessary that the proposed radiation protection program in this work is applied.

  11. Mammography Prevalence within 2 Two Years (Age 40+) - Small Area Estimates

    Cancer.gov

    For mammography, a woman 40 years of age or older must have reported having at least one mammography in her life. Furthermore, she should have had the most recent one within the last two years by the time of interview.

  12. Performance of a new digital flat-panel detector system in the detection of simulated rheumatoid erosions: a comparison with a speed-class 200 screen-film system, a mammography screen-film system, and a storage-phosphor system at different levels of exposure.

    NASA Astrophysics Data System (ADS)

    Ludwig, Karl; Henschel, Andreas; Bernhardt, Thomas; Lenzen, Horst; Wormanns, Dag; Diederich, Stefan; Heindel, Walter

    2002-05-01

    The purpose of this study was to compare a large-area direct read-out flat-panel detector system with a speed class 200 screen-film system, a storage-phosphor system and a mammography screen-film system with regard to the detection of simulated rheumatoid erosions and to assess its diagnostic performance with decreasing exposure dose. The performance of a flat-panel system in such small lesions was considered especially interesting, as the spatial resolution of this system, limited by its pixel size, is considerably lower than that of conventional screen-film systems. An animal model with 160 joint specimens from 20 monkey paws was used. 640 regions were defined in these 160 meta- carpophalangeal and proximal interphalangeal joint specimens. Simulated rheumatoid erosions were created in 320 of these 640 regions. Specimens were enclosed in containers filed with water to obtain absorption and scatter radiation conditions similar to a human hand. Imaging was performed using a flat-panel system, a sped class 200 screen-film system, a mammography screen-film system and a storage- phosphor system under exactly matched conditions. Different exposure doses equivalent to speed classes of S equals 100, 200, 400, 800, 1600 and 3200 were used. Presence or absence of a lesion was assessed by three radiologists using a five level confidence scale. Receiver operating characteristic analysis was performed for a total of 21,120 observations and diagnostic performance estimated by the area under the ROC curve. The significance of differences between Az values was tested with analysis of variance. ROC-analysis showed Az values of 0.809, 0.768, 0.737, 0.710 and 0.685 for the flat-panel system, 0.770 for the screen-film system, 0.781, 0.739, 0.724 and 0.680 for the storage-phosphor system, and 0.798 for the mammography screen-film system. Analysis of variance showed significant differences for certain combinations of imaging modalities and exposure doses. The diagnostic performance of

  13. Mammography screening. Benefits, harms, and informed choice.

    PubMed

    Jørgensen, Karsten Juhl

    2013-04-01

    The rationale for breast cancer screening with mammography is deceptively simple: catch it early and reduce mortality from the disease and the need for mastectomies. But breast cancer is a complex problem, and complex problems rarely have simple solutions. Breast screening brings forward the time of diagnosis only slightly compared to the lifetime of a tumour, and screen-detected tumours have a size where metastases are possible. A key question is if screening can prevent metastases, and if the screen-detected tumours are small enough to allow breast conserving surgery rather than mastectomy. A mortality reduction can never justify a medical intervention in its own right, but must be weighed against the harms. Overdiagnosis is the most important harm of breast screening, but has gained wider recognition only in recent years. Screening leads to the detection and treatment of breast cancers that would otherwise never have been detected because they grow very slowly or not at all and would not have been detected in the woman's lifetime in the absence of screening. Screening therefore turns women into cancer patients unnecessarily, with life-long physical and psychological harms. The debate about the justification of breast screening is therefore not a simple question of whether screening reduces breast cancer mortality. This dissertation quantifies the primary benefits and harms of screening mammography. Denmark has an unscreened "control group" because only two geographical regions offered screening over a long time-period, which is unique in an international context. This was used to study breast cancer mortality, overdiagnosis, and the use of mastectomies. Also, a systematic review of overdiagnosis in five other countries allowed us to show that about half of the screen-detected breast cancers are overdiagnosed. An effect on breast cancer mortality is doubtful in today's setting, and overdiagnosis causes an increase in the use of mastectomies. These findings are

  14. The Assessment of the Likelihood of Mammography Usage with Relevant Factors among Women with Disabilities

    ERIC Educational Resources Information Center

    Kung, Pei-Tseng; Tsai, Wen-Chen; Chiou, Shang-Jyh

    2012-01-01

    Research that identifies the determinants of low mammography use among disabled people is scant. This study examines the determining factors related to the low usage of mammography among women with disabilities. To identify the barriers that prevent women with disabilities from participating in mammography screening can help authorities conceive…

  15. 42 CFR 405.534 - Limitation on payment for screening mammography services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Limitation on payment for screening mammography... for Determining Reasonable Charges § 405.534 Limitation on payment for screening mammography services... January 1, 1991 until December 31, 2001. Screening mammography services provided after December 31,...

  16. 42 CFR 413.123 - Payment for screening mammography performed by hospitals on an outpatient basis.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Payment for screening mammography performed by... SKILLED NURSING FACILITIES Specific Categories of Costs § 413.123 Payment for screening mammography... mammographies performed by hospitals. (b) Payment to hospitals for outpatient services. Payment to hospitals...

  17. 42 CFR 405.535 - Special rule for nonparticipating physicians and suppliers furnishing screening mammography...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... suppliers furnishing screening mammography services before January 1, 2002. 405.535 Section 405.535 Public... Special rule for nonparticipating physicians and suppliers furnishing screening mammography services before January 1, 2002. The provisions in this section apply for screening mammography services...

  18. Response costs of mammography adherence: Iranian women’s perceptions

    PubMed Central

    Khodayarian, Mahsa; Mazloomi-Mahmoodabad, Seyed Saied; Lamyian, Minoor; Morowatisharifabad, Mohammad Ali; Tavangar, Hossein

    2016-01-01

    Background: Mammography as the most common secondary prevention method has known to be helpful in detecting breast cancer at the early stages. Low level of participation among women toward mammography uptake due to cultural beliefs is a great concern. This study aimed at exploring the perceptions of women about response costs of mammography adherence (MA) in Yazd, Iran. Methods: A qualitative study using semi-structured interviews was performed. Fourteen women,one oncology nurse, and a breast cancer survivor were purposefully interviewed. Interviews were transcribed verbatim and analyzed by directed content analysis method based on protection motivation theory (PMT). Results: One main theme was emerged from the analysis namely called "response costs".Two main categories were also emerged from the data; (1) psychological barriers with six subcategories including "embarrassment," "worry about being diagnosed with cancer," "preoccupation with underlying disease," "misconception about mammography," "need for an accompanying person," and "internalizing the experiences of the others," and (2) maladaptive coping modes which encompassed three subcategories: "religious faith," "fatalism," and"avoidance and denial." Conclusion: Useful information was provided about the response costs of mammography utilization based on the perceptions of women. Cognitive barriers may be decreased by conducting modifications in women’s awareness and attitude toward MA as well as changing the national health system infrastructures. Incorporating religious and cultural belief systems into MA educational programs through motivational messages is recommended. PMID:27386423

  19. Mammography Findings of Male Breast Diseases

    PubMed Central

    Şafak, Kadihan Yalçın

    2015-01-01

    Over the past 2 decades, the percentage of men presenting with breast complaints has increased from 0.8% to 2.4%, and men now account for 1% of all breast cancer cases. The most common male breast mass is gynecomastia, followed by lipoma and epidermal inclusion cysts. Because there is a paucity of parenchyma as compared with the female breast, the malignancy rapidly progresses to the next stage, with the appearance of secondary signs like nipple retraction, fixation to deeper tissues, skin ulceration or adenopathy. Diagnostic evaluation is needed only when the palpable mass is unilateral, hard, fixed, peripheral to the nipple, or associated with nipple discharge, skin changes, or lymphadenopathy. Male breast cancer usually occurs in a subareolar location or is positioned eccentric to the nipple; occasionally, it occurs in a peripheral position. Secondary signs like skin thickening, nipple retraction, and axillary lymphadenopathy may be seen. Microcalcifications can occur. Mammography can accurately distinguish between malignant and benign male breast disease. Radiologists are generally less familiar with breast disease in males compared with females. In this article, we discuss the clinical, and mammographic features of a variety of benign and malignant diseases that can occur in the male breast.

  20. Image toggling saves time in mammography

    PubMed Central

    Drew, Trafton; Aizenman, Avi M.; Thompson, Matthew B.; Kovacs, Mark D.; Trambert, Michael; Reicher, Murray A.; Wolfe, Jeremy M.

    2015-01-01

    Abstract. When two images are perfectly aligned, even subtle differences are readily detected when the images are “toggled” back and forth in the same location. However, substantial changes between two photographs can be missed if the images are misaligned (“change blindness”). Nevertheless, recent work from our lab, testing nonradiologists, suggests that toggling misaligned photographs leads to superior performance compared to side-by-side viewing (SBS). In order to determine if a benefit of toggling misaligned images may be observed in clinical mammography, we developed an image toggling technique where pairs of new and prior breast imaging exam images could be efficiently toggled back and forth. Twenty-three radiologists read 10 mammograms evenly divided in toggle and SBS modes. The toggle mode led to a 6-s benefit in reaching a decision [t(22)=5.11, p<.05]. The toggle viewing mode also led to a 5% improvement in diagnostic accuracy, though in our small sample this effect was not statistically reliable. Time savings were found even though successive mammograms were not perfectly aligned. Given the ever-increasing caseload for radiologists, this simple manipulation of how the images are viewed could save valuable time in clinical practice, allowing radiologists to read more cases or spend more time on difficult cases. PMID:26870746

  1. Advantages and Disadvantages of Mammography Screening

    PubMed Central

    Heywang-Köbrunner, Sylvia H.; Hacker, Astrid; Sedlacek, Stefan

    2011-01-01

    Summary Mammography screening is the only method presently considered appropriate for mass screening of asymptomatic women. Its frequent use, however, warrants diligent analysis of potential side effects. Radiation risk is far below the natural yearly risk of breast cancer and should not be used as an argument against screening. False-positive calls lead to additional imaging or histopathological assessment, mainly percutaneous breast biopsy. These measures are tolerated and accepted fairly well. Their number is limited by strict quality assurance and constant training. Interval cancers represent a limitation of breast screening that should prompt further research for optimization. Evaluation of overdiagnosis is a highly debated topic in the literature. According to the probably most realistic available calculations, overdiagnosis is acceptable as it is compensated by the potential mortality reduction. Nonetheless, this potential side effect warrants optimal adjustment of therapy to the patient's individual risk. The mortality reduction seen in randomized studies was confirmed by results from national screening programs. A recent case referent study indicated that improvements in mortality reduction run parallel to improved mammographic techniques. Use of less aggressive therapies is another valuable effect of screening. Awareness of potential problems, strict quality assurance, and further research should help to further develop screening programs. PMID:21779225

  2. Feasibility of using LODOX technology for mammography

    NASA Astrophysics Data System (ADS)

    Lease, Alyson; Vaughan, Christopher; Beningfield, Stephan; Potgieter, Herman; Booysen, Andre

    2002-05-01

    The LODOX (Low Dose X-ray) Scanner, created by De Beers, is currently being clinically tested at the Trauma Unit of Groote Schuur Hospital and the University of Cape Town in South Africa. High quality images with exceedingly low radiation suggest that the technology may also be used to identify breast cancer lesions and microcalcifications. The measured LODOX modulation transfer function averages 6 percent at 10 cycles per millimeter, while the detected quantum efficiency is approximately 25 percent at 1 cycle per millimeter. The mean glandular doses calculated for a breast thickness of 4 cm at various intensities -- ranging from 0.022 rad at 70mAs to 0.043 rad at 125mAs -- were approximately 10 times less than the value designated by the American College of Radiology (0.3 rad per breast image). At 40kV, LODOX exhibits an average half value layer of 1.59 mm of Al (compared to 0.3 to 0.4 mm recommended for mammography), illustrating the unfavorable higher penetration of LODOX X-rays. The extremely low radiation dose delivered by the LODOX suggests that the technology would be feasible for detecting and diagnosing cancers in the sensitive tissue of the breast, once adjustments to X-ray range and beam hardness had been accomplished.

  3. Latin American dose survey results in mammography studies under IAEA programme: radiological protection of patients in medical exposures (TSA3).

    PubMed

    Mora, Patricia; Blanco, Susana; Khoury, Helen; Leyton, Fernando; Cárdenas, Juan; Defaz, María Yolanda; Garay, Fernando; Telón, Flaviano; Aguilar, Juan Garcia; Roas, Norma; Gamarra, Mirtha; Blanco, Daniel; Quintero, Ana Rosa; Nader, Alejandro

    2015-03-01

    Latin American countries (Argentina, Brazil, Chile, Costa Rica, Cuba, Ecuador, El Salvador, Guatemala, Mexico, Nicaragua, Paraguay, Uruguay and Venezuela) working under the International Atomic Energy Agency (IAEA) Technical Cooperation Programme: TSA3 Radiological Protection of Patients in Medical Exposures have joined efforts in the optimisation of radiation protection in mammography practice. Through surveys of patient doses, the region has a unique database of diagnostic reference levels for analogue and digital equipment that will direct future optimisation activities towards the early detection of breast cancer among asymptomatic women. During RLA9/057 (2007-09) 24 institutions participated with analogue equipment in a dose survey. Regional training on methodology and measurement equipment was addressed in May 2007. The mean glandular dose (DG) was estimated using the incident kerma in air and relevant conversion coefficients for both projections craneo caudal and mediolateral oblique (CC and MLO). For Phase 2, RLA9/067 (2010-11), it was decided to include also digital systems in order to see their impact in future dose optimisation activities. Any new country that joined the project received training in the activities through IAEA expert missions. Twenty-nine new institutions participated (9 analogue and 20 digital equipment). A total of 2262 patient doses were collected during this study and from them D(G) (mGy) for both projections were estimated for each institution and country. Regional results (75 percentile in mGy) show for CC and MLO views, respectively: RLA9/057 (analogue) 2.63 and 3.17; RLA/067: 2.57 and 3.15 (analogue) and 2.69 and 2.90 (digital). Regarding only digital equipment for CC and MLO, respectively, computed radiography systems showed 2.59 and 2.78 and direct digital radiography (DDR) systems 2.78 and 3.04. Based on the IAEA Basic Safety Standard (BSS) reference dose (3 mGy), it can be observed that there is enough room to start

  4. Characterization of TLD-100 micro-cubes for use in small field dosimetry

    SciTech Connect

    Peña-Jiménez, Salvador Gamboa-deBuen, Isabel; Lárraga-Gutiérrez, José Manuel E-mail: amanda.garcia.g@gmail.com; García-Garduño, Olivia Amanda E-mail: amanda.garcia.g@gmail.com

    2014-11-07

    At present there are no international regulations for the management of millimeter scale fields and there are no suggestions for a reference detector to perform the characterization and dose determination for unconventional radiation beams (small fields) so that the dosimetry of small fields remains an open research field worldwide because these fields are used in radiotherapy treatments. Sensitivity factors and reproducibility of TLD-100 micro-cubes (1×1×1 mm3) were determinate irradiating the dosimeters with a 6 MV beam in a linear accelerator dedicated to radiosurgery at the Instituto Nacional de Neurología y Neurocirugía (INNN). Thermoluminescent response as a function of dose was determined for doses in water between 0.5 and 3 Gy and two field sizes (2×2 cm2 and 10×10 cm2). It was found that the response is linear over the dose range studied and it does not depend on field size.

  5. Characterization of TLD-100 micro-cubes for use in small field dosimetry

    NASA Astrophysics Data System (ADS)

    Peña-Jiménez, Salvador; Lárraga-Gutiérrez, José Manuel; García-Garduño, Olivia Amanda; Gamboa-deBuen, Isabel

    2014-11-01

    At present there are no international regulations for the management of millimeter scale fields and there are no suggestions for a reference detector to perform the characterization and dose determination for unconventional radiation beams (small fields) so that the dosimetry of small fields remains an open research field worldwide because these fields are used in radiotherapy treatments. Sensitivity factors and reproducibility of TLD-100 micro-cubes (1×1×1 mm3) were determinate irradiating the dosimeters with a 6 MV beam in a linear accelerator dedicated to radiosurgery at the Instituto Nacional de Neurología y Neurocirugía (INNN). Thermoluminescent response as a function of dose was determined for doses in water between 0.5 and 3 Gy and two field sizes (2×2 cm2 and 10×10 cm2). It was found that the response is linear over the dose range studied and it does not depend on field size.

  6. Characterisation of a high resolution small field of view portable gamma camera.

    PubMed

    Bugby, S L; Lees, J E; Bhatia, B S; Perkins, A C

    2014-05-01

    A handheld, high-resolution small field of view (SFOV) pinhole gamma camera has been characterised using a new set of protocols adapted from standards previously developed for large field of view (LFOV) systems. Parameters investigated include intrinsic and extrinsic spatial resolution, spatial linearity, uniformity, sensitivity, count rate capability and energy resolution. Camera characteristics are compared to some clinical LFOV gamma cameras and also to other SFOV cameras in development.

  7. Comparison of the polynomial model against explicit measurements of noise components for different mammography systems

    NASA Astrophysics Data System (ADS)

    Monnin, P.; Bosmans, H.; Verdun, F. R.; Marshall, N. W.

    2014-10-01

    Given the adverse impact of image noise on the perception of important clinical details in digital mammography, routine quality control measurements should include an evaluation of noise. The European Guidelines, for example, employ a second-order polynomial fit of pixel variance as a function of detector air kerma (DAK) to decompose noise into quantum, electronic and fixed pattern (FP) components and assess the DAK range where quantum noise dominates. This work examines the robustness of the polynomial method against an explicit noise decomposition method. The two methods were applied to variance and noise power spectrum (NPS) data from six digital mammography units. Twenty homogeneously exposed images were acquired with PMMA blocks for target DAKs ranging from 6.25 to 1600 µGy. Both methods were explored for the effects of data weighting and squared fit coefficients during the curve fitting, the influence of the additional filter material (2 mm Al versus 40 mm PMMA) and noise de-trending. Finally, spatial stationarity of noise was assessed. Data weighting improved noise model fitting over large DAK ranges, especially at low detector exposures. The polynomial and explicit decompositions generally agreed for quantum and electronic noise but FP noise fraction was consistently underestimated by the polynomial method. Noise decomposition as a function of position in the image showed limited noise stationarity, especially for FP noise; thus the position of the region of interest (ROI) used for noise decomposition may influence fractional noise composition. The ROI area and position used in the Guidelines offer an acceptable estimation of noise components. While there are limitations to the polynomial model, when used with care and with appropriate data weighting, the method offers a simple and robust means of examining the detector noise components as a function of detector exposure.

  8. Comparison of model and human observer performance in FFDM, DBT, and synthetic mammography

    NASA Astrophysics Data System (ADS)

    Ikejimba, Lynda; Glick, Stephen J.; Samei, Ehsan; Lo, Joseph Y.

    2016-03-01

    Reader studies are important in assessing breast imaging systems. The purpose of this work was to assess task-based performance of full field digital mammography (FFDM), digital breast tomosynthesis (DBT), and synthetic mammography (SM) using different phantom types, and to determine an accurate observer model for human readers. Images were acquired on a Hologic Selenia Dimensions system with a uniform and anthropomorphic phantom. A contrast detail insert of small, low-contrast disks was created using an inkjet printer with iodine-doped ink and inserted in the phantoms. The disks varied in diameter from 210 to 630 μm, and in contrast from 1.1% contrast to 2.2% in regular increments. Human and model observers performed a 4-alternative forced choice experiment. The models were a non-prewhitening matched filter with eye model (NPWE) and a channelized Hotelling observer with either Gabor channels (Gabor-CHO) or Laguerre-Gauss channels (LG-CHO). With the given phantoms, reader scores were higher in FFDM and DBT than SM. The structure in the phantom background had a bigger impact on outcome for DBT than for FFDM or SM. All three model observers showed good correlation with humans in the uniform background, with ρ between 0.89 and 0.93. However, in the structured background, only the CHOs had high correlation, with ρ=0.92 for Gabor-CHO, 0.90 for LG-CHO, and 0.77 for NPWE. Because results of any analysis can depend on the phantom structure, conclusions of modality performance may need to be taken in the context of an appropriate model observer and a realistic phantom.

  9. Evaluation of detector dynamic range in the x-ray exposure domain in mammography: a comparison between film-screen and flat panel detector systems.

    PubMed

    Cooper, Virgil N; Oshiro, Thomas; Cagnon, Christopher H; Bassett, Lawrence W; McLeod-Stockmann, Tyler M; Bezrukiy, Nikita V

    2003-10-01

    Digital detectors in mammography have wide dynamic range in addition to the benefit of decoupled acquisition and display. How wide the dynamic range is and how it compares to film-screen systems in the clinical x-ray exposure domain are unclear. In this work, we compare the effective dynamic ranges of film-screen and flat panel mammography systems, along with the dynamic ranges of their component image receptors in the clinical x-ray exposure domain. An ACR mammography phantom was imaged using variable mAs (exposure) values for both systems. The dynamic range of the contrast-limited film-screen system was defined as that ratio of mAs (exposure) values for a 26 kVp Mo/Mo (HVL=0.34 mm Al) beam that yielded passing phantom scores. The same approach was done for the noise-limited digital system. Data from three independent observers delineated a useful phantom background optical density range of 1.27 to 2.63, which corresponded to a dynamic range of 2.3 +/- 0.53. The digital system had a dynamic range of 9.9 +/- 1.8, which was wider than the film-screen system (p<0.02). The dynamic range of the film-screen system was limited by the dynamic range of the film. The digital detector, on the other hand, had an estimated dynamic range of 42, which was wider than the dynamic range of the digital system in its entirety by a factor of 4. The generator/tube combination was the limiting factor in determining the digital system's dynamic range.

  10. Mammographic imaging with a small format CCD-based digital cassette: Physical characteristics of a clinical systema

    PubMed Central

    Vedantham, Srinivasan; Karellas, Andrew; Suryanarayanan, Sankararaman; Levis, Ilias; Sayag, Michel; Kleehammer, Robert; Heidsieck, Robert; D’Orsi, Carl J.

    2008-01-01

    The physical characteristics of a clinical charge coupled device (CCD)-based imager (Senovision, GE Medical Systems, Milwaukee, WI) for small-field digital mammography have been investigated. The imager employs a MinR 2000™ (Eastman Kodak Company, Rochester, NY) scintillator coupled by a 1:1 optical fiber to a front-illuminated 61×61 mm CCD operating at a pixel pitch of 30 microns. Objective criteria such as modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), and noise equivalent quanta (NEQ) were employed for this evaluation. The results demonstrated a limiting spatial resolution (10% MTF) of 10 cy/mm. The measured DQE of the current prototype utilizing a 28 kVp, Mo–Mo spectrum beam hardened with 4.5 cm Lucite is ~40% at close to zero spatial frequency at an exposure of 8.2 mR, and decreases to ~28% at a low exposure of 1.1 mR. Detector element nonuniformity and electronic gain variations were not significant after appropriate calibration and software corrections. The response of the imager was linear and did not exhibit signal saturation under tested exposure conditions. PMID:10984230

  11. Patterns and determinants of mammography screening in Lebanese women.

    PubMed

    Elias, Nadia; Bou-Orm, Ibrahim R; Adib, Salim M

    2017-03-01

    The associations of ever using and/or repeating a mammography test with psychosocial and socio-demographic factors were surveyed in 2014 among Lebanese women ≥ 40. A sample of 2400 women was selected across Lebanon. Variables with significant bivariate associations with various types of behaviors were entered in multivariate analysis. Of the total, 105 women (4·4%) had never heard of mammography as a tool for early breast cancer detection. Among the remaining 2295, 45% had ever used it, of whom 10% had obtained it for the first time within the 12 months preceding the survey. Repeaters were 67% of 926 women who had the time opportunity to do so (median lifetime frequency: 2). Older age, higher socio-economic status (SES) and living within the Greater Beirut (GB) area were significantly associated with ever-use. Within GB, psychosocial factors such as perceived susceptibility and benefits were most strongly associated with ever-use. Outside GB, socio-economic advantage seemed to mostly affect ever-use. Only 4% reported opposition from husbands to their mammography, and husband's support was significant for adherence to mammography guidelines mostly outside GB. Higher education emerged also as a significant socio-demographic determinant for ever-repeating in all regions. Perceived comfort of the previous test strongly affected the likelihood of repeating it. Providing mammography free-of-charge may alleviate some obstacles among women with socio-economic disadvantage. Stressing that good results one year do not make the cancer less likely or repeating the test less important, as well as improving the comfort of mammography testing could ensure test repeating.

  12. The effect of small field output factor measurements on IMRT dosimetry

    SciTech Connect

    Azimi, Rezvan; Alaei, Parham; Higgins, Patrick

    2012-08-15

    Purpose: To evaluate how changes in the measured small field output factors affect the doses in intensity-modulated treatment planning. Methods: IMRT plans were created using Philips Pinnacle treatment planning system. The plans were optimized to treat a cylindrical target 2 cm in diameter and 2 cm in length. Output factors for 2 Multiplication-Sign 2 and 3 Multiplication-Sign 3 cm{sup 2} field sizes were changed by {+-}5%, {+-}10%, and {+-}20% increments from the baseline measurements and entered into the planning system. The treatment units were recommissioned in the treatment planning system after each modification of the output factors and treatment plans were reoptimized. All plans were delivered to a solid water phantom and dose measurements were made using an ionization chamber. The percentage differences between measured and computed doses were calculated. An Elekta Synergy and a Varian 2300CD linear accelerator were separately evaluated. Results: For the Elekta unit, decreasing the output factors resulted in higher measured than computed doses by 0.8% for -5%, 3.6% for -10%, and 8.7% for -20% steps. Increasing the output factors resulted in lower doses by 2.9% for +5%, 5.4% for +10%, and 8.3% for +20% steps. For the Varian unit no changes were observed for either increased or decreased output factors. Conclusions: The measurement accuracy of small field output factors are of importance especially when the treatment plan consists of small segments as in IMRT. The method proposed here could be used to verify the accuracy of the measured small field output factors for certain linear accelerators as well as to test the beam model. The Pinnacle treatment planning system model uses output factors as a function of jaw setting. Consequently, plans using the Elekta unit, which conforms the jaws to the segments, are sensitive to small field measurement accuracy. On the other hand, for the Varian unit, jaws are fixed and segments are modeled as blocked fields hence

  13. SU-E-T-358: Monte Carlo Dose Calculation of Small Field Electron Beams

    SciTech Connect

    Wu, Q; Rodrigues, A; Yin, F; Sawkey, D

    2014-06-01

    Purpose: Dynamic radiotherapy involving electron beams such as Dynamic Electron Arc Radiotherapy (DEAR) requires accurate dose modelling of small field sizes, similar to the requirement of IMRT field on the small photon field. The current commercial electron Monte Carlo algorithms such as eMC v11 in Eclipse were developed for standard field sizes and do not support the planning of dynamic therapy yet. The purpose of this study is to develop a method to accurately model small field electron beam dosimetry using Monte Carlo simulations. Methods: Comparison between eMC, phantom measurements (diode), and Monte Carlo (MC) simulations (BEAMnrc/DOSYZnrc) were performed for a Varian TrueBeam linac. MC simulations utilized Varian TrueBeam phase space files which had been validated in another study. Static single small field was assessed by comparing dose distributions in water for a 16 MeV beam for circular (2 cm diameter) and rectangular (1×10 cm{sup 2}) cut-out. MC was performed with a resolution of 2.5×2.5×2 mm{sup 2} and statistical uncertainty < 4%. The dose distribution was averaged over adjacent bins to improve precision. Depth dose and orthogonal profiles were evaluated. Results: Small field PDDs differ from those with standard cones. For both circular and rectangular cutouts, the difference in range R8 0-R1 0 is less than 2 mm and in dose within 2%. For the orthogonal profiles, field size and penumbra differences were within 1 mm at depth of maximum dose. The eMC displayed a distinctive “step” in the out-field dose profile in disagreement with both measurement and MC results and needs further investigation. Conclusion: MC was able to characterize the small field dosimetry with good agreement with the measurement data, and thus offers the opportunity for treatment planning of dynamic radiotherapy. Analyses for all other electron energies and cut-out sizes are under way and results will be included in the presentation.

  14. Monte Carlo-based diode design for correction-less small field dosimetry.

    PubMed

    Charles, P H; Crowe, S B; Kairn, T; Knight, R T; Hill, B; Kenny, J; Langton, C M; Trapp, J V

    2013-07-07

    Due to their small collecting volume, diodes are commonly used in small field dosimetry. However, the relative sensitivity of a diode increases with decreasing small field size. Conversely, small air gaps have been shown to cause a significant decrease in the sensitivity of a detector as the field size is decreased. Therefore, this study uses Monte Carlo simulations to look at introducing air upstream to diodes such that they measure with a constant sensitivity across all field sizes in small field dosimetry. Varying thicknesses of air were introduced onto the upstream end of two commercial diodes (PTW 60016 photon diode and PTW 60017 electron diode), as well as a theoretical unenclosed silicon chip using field sizes as small as 5 mm × 5 mm. The metric D(w,Q)/D(Det,Q) used in this study represents the ratio of the dose to a point of water to the dose to the diode active volume, for a particular field size and location. The optimal thickness of air required to provide a constant sensitivity across all small field sizes was found by plotting D(w,Q)/D(Det,Q) as a function of introduced air gap size for various field sizes, and finding the intersection point of these plots. That is, the point at which D(w,Q)/D(Det,Q) was constant for all field sizes was found. The optimal thickness of air was calculated to be 3.3, 1.15 and 0.10 mm for the photon diode, electron diode and unenclosed silicon chip, respectively. The variation in these results was due to the different design of each detector. When calculated with the new diode design incorporating the upstream air gap, k(f(clin),f(msr))(Q(clin),Q(msr)) was equal to unity to within statistical uncertainty (0.5%) for all three diodes. Cross-axis profile measurements were also improved with the new detector design. The upstream air gap could be implanted on the commercial diodes via a cap consisting of the air cavity surrounded by water equivalent material. The results for the unclosed silicon chip show that an ideal small

  15. Monte Carlo-based diode design for correction-less small field dosimetry

    NASA Astrophysics Data System (ADS)

    Charles, P. H.; Crowe, S. B.; Kairn, T.; Knight, R. T.; Hill, B.; Kenny, J.; Langton, C. M.; Trapp, J. V.

    2013-07-01

    Due to their small collecting volume, diodes are commonly used in small field dosimetry. However, the relative sensitivity of a diode increases with decreasing small field size. Conversely, small air gaps have been shown to cause a significant decrease in the sensitivity of a detector as the field size is decreased. Therefore, this study uses Monte Carlo simulations to look at introducing air upstream to diodes such that they measure with a constant sensitivity across all field sizes in small field dosimetry. Varying thicknesses of air were introduced onto the upstream end of two commercial diodes (PTW 60016 photon diode and PTW 60017 electron diode), as well as a theoretical unenclosed silicon chip using field sizes as small as 5 mm × 5 mm. The metric \\frac{{D_{w,Q} }}{{D_{Det,Q} }} used in this study represents the ratio of the dose to a point of water to the dose to the diode active volume, for a particular field size and location. The optimal thickness of air required to provide a constant sensitivity across all small field sizes was found by plotting \\frac{{D_{w,Q} }}{{D_{Det,Q} }} as a function of introduced air gap size for various field sizes, and finding the intersection point of these plots. That is, the point at which \\frac{{D_{w,Q} }}{{D_{Det,Q} }} was constant for all field sizes was found. The optimal thickness of air was calculated to be 3.3, 1.15 and 0.10 mm for the photon diode, electron diode and unenclosed silicon chip, respectively. The variation in these results was due to the different design of each detector. When calculated with the new diode design incorporating the upstream air gap, k_{Q_{clin} ,Q_{msr} }^{f_{clin} ,f_{msr} } was equal to unity to within statistical uncertainty (0.5%) for all three diodes. Cross-axis profile measurements were also improved with the new detector design. The upstream air gap could be implanted on the commercial diodes via a cap consisting of the air cavity surrounded by water equivalent material. The

  16. Mammography use and mode of detection among breast cancer patients in Estonia.

    PubMed

    Innos, Kaire; Valvere, Vahur; Padrik, Peeter; Eelma, Evelyn; Kütner, Riina; Lehtsaar, Jaak; Tekkel, Mare

    2016-01-01

    The aim of this study was to examine past mammography use and mode of detection among breast cancer (BC) patients in Estonia, a country that has low screening coverage and high BC mortality. Women newly diagnosed with primary BC in Estonia in 2008-2010 were interviewed. Determinants of past mammography use and the detection of BC by mammography were studied using multivariate logistic regression. Among 977 participants, almost half reported no mammograms prior to the detection of BC. Overall, 22% of the cases were detected by mammography (16% by screening mammography). Detection by mammography was strongly related to age, past mammography use, and obesity. Among cases detected by mammography, 10% were stage III/IV at diagnosis (32% among cases detected by other modes). This study showed low mammography utilization and high rate of self-detection of BC in Estonia. Increased detection by mammography would help diagnose the disease at an earlier stage and consequently avoid premature BC deaths. Efforts should be undertaken to increase participation in screening and improve the availability of mammography among older and high-risk women. The results are likely to be relevant for other countries and population groups with low screening coverage.

  17. Positron Emission Mammography with Multiple Angle Acquisition

    SciTech Connect

    Mark F. Smith; Stan Majewski; Raymond R. Raylman

    2002-11-01

    Positron emission mammography (PEM) of F-18 fluorodeoxyglucose (FDG) uptake in breast tumors with dedicated detectors typically has been accomplished with two planar detectors in a fixed position with the breast under compression. The potential use of PEM imaging at two detector positions to guide stereotactic breast biopsy has motivated us to use PEM coincidence data acquired at two or more detector positions together in a single image reconstruction. Multiple angle PEM acquisition and iterative image reconstruction were investigated using point source and compressed breast phantom acquisitions with 5, 9, 12 and 15 mm diameter spheres and a simulated tumor:background activity concentration ratio of 6:1. Image reconstruction was performed with an iterative MLEM algorithm that used coincidence events between any two detector pixels on opposed detector heads at each detector position. This present study compared two acquisition protocols: 2 angle acquisition with detector angular positions of -15 and +15 degrees and 11 angle acquisition with detector positions spaced at 3 degree increments over the range -15 to +15 degrees. Three- dimensional image resolution was assessed for the point source acquisitions, and contrast and signal-to-noise metrics were evaluated for the compressed breast phantom with different simulated tumor sizes. Radial and tangential resolutions were similar for the two protocols, while normal resolution was better for the 2 angle acquisition. Analysis is complicated by the asymmetric point spread functions. Signal- to-noise vs. contrast tradeoffs were better for 11 angle acquisition for the smallest visible 9 mm sphere, while tradeoff results were mixed for the larger and more easily visible 12 mm and 15 mm diameter spheres. Additional study is needed to better understand the performance of limited angle tomography for PEM. PEM tomography experiments with complete angular sampling are planned.

  18. Positron Emission Mammography with Multiple Angle Acquisition

    SciTech Connect

    Mark F. Smith; Stan Majewski; Raymond R. Raylman

    2002-11-01

    Positron emission mammography (PEM) of F-18 fluorodeoxyglucose (FbG) uptake in breast tumors with dedicated detectors typically has been accomplished with two planar detectors in a fixed position with the breast under compression. The potential use of PEM imaging at two detector positions to guide stereotactic breast biopsy has motivated us to use PEM coincidence data acquired at two or more detector positions together in a single image reconstruction. Multiple angle PEM acquisition and iterative image reconstruction were investigated using point source and compressed breast phantom acquisitions with 5, 9, 12 and 15 mm diameter spheres and a simulated tumor:background activity concentration ratio of 6:1. Image reconstruction was performed with an iterative MLEM algorithm that used coincidence events between any two detector pixels on opposed detector heads at each detector position. This present study compared two acquisition protocols: 2 angle acquisition with detector angular positions of -15 and +15 degrees and 11 angle acquisition with detector positions spaced at 3 degree increments over the range -15 to +15 degrees. Three-dimensional image resolution was assessed for the point source acquisitions, and contrast and signal-to-noise metrics were evaluated for the compressed breast phantom with different simulated tumor sizes. Radial and tangential resolutions were similar for the two protocols, while normal resolution was better for the 2 angle acquisition. Analysis is complicated by the asymmetric point spread functions. Signal- to-noise vs. contrast tradeoffs were better for 11 angle acquisition for the smallest visible 9 mm sphere, while tradeoff results were mixed for the larger and more easily visible 12 mm and 15 mm diameter spheres. Additional study is needed to better understand the performance of limited angle tomography for PEM. PEM tomography experiments with complete angular sampling are planned.

  19. The impact of a physician intervention program on older women's mammography use.

    PubMed

    Preston, J A; Grady, J N; Schulz, A F; Petrillo, M K; Scinto, J D

    1998-12-01

    The Mammography Optimum Referral Effort (MORE) is a physician office-based intervention program initiated by the Connecticut Peer Review Organization (CPRO) to increase mammography use among older women in Connecticut. Three locales in the state were targeted for the MORE intervention based on identified low mammography rates in women aged 65 years and older. Thirty-seven physicians participated from March 1, 1996, to August 31, 1996. Annual mammography rates were derived by merging Medicare Part B mammography claims with a database from the Connecticut Tumor Registry. This strategy allowed us to exclude women with a prior history of breast cancer from the analysis, in order to estimate screening rates. The MORE intervention was associated with an absolute increase of 5.9%, which represents a relative increase of 15.4%, in annual mammography use. Our findings suggest that a multifaceted physician intervention is capable of increasing mammography use among older women.

  20. Assessment of Mean Glandular Dose in Mammography System with Different Anode-Filter Combinations Using MCNP Code

    PubMed Central

    Gholamkar, Lida; Mowlavi, Ali Asghar; Sadeghi, Mahdi; Athari, Mitra

    2016-01-01

    Background X-ray mammography is one of the general methods for early detection of breast cancer. Since glandular tissue in the breast is sensitive to radiation and it increases the risk of cancer, the given dose to the patient is very important in mammography. Objectives The aim of this study was to determine the average absorbed dose of X-ray radiation in the glandular tissue of the breast during mammography examinations as well as investigating factors that influence the mean glandular dose (MGD). One of the precise methods for determination of MGD absorbed by the breast is Monte Carlo simulation method which is widely used to assess the dose. Materials and Methods We studied some different X-ray sources and exposure factors that affect the MGD. “Midi-future” digital mammography system with amorphous-selenium detector was simulated using the Monte Carlo N-particle extended (MCNPX) code. Different anode/filter combinations such as tungsten/silver (W/Ag), tungsten/rhodium (W/Rh), and rhodium/aluminium (Rh/Al) were simulated in this study. The voltage of X-ray tube ranged from 24 kV to 32 kV with 2 kV intervals and the breast phantom thickness ranged from 3 to 8 cm, and glandular fraction g varied from 10% to 100%. Results MGD was measured for different anode/filter combinations and the effects of changing tube voltage, phantom thickness, combination and glandular breast tissue on MGD were studied. As glandular g and X-ray tube voltage increased, the breast dose increased too, and the increase of breast phantom thickness led to the decrease of MGD. The obtained results for MGD were consistent with the result of Boone et al. that was previously reported. Conclusion By comparing the results, we saw that W/Rh anode/filter combination is the best choice in breast mammography imaging because of the lowest delivered dose in comparison with W/Ag and Rh/Al. Moreover, breast thickness and g value have significant effects on MGD. PMID:27895876

  1. Quantitative analysis of performance of selenium flat-panel detector for interventional mammography

    NASA Astrophysics Data System (ADS)

    Debrie, Anne; Polischuk, Brad T.; Rougeot, Henri; Hansroul, Marc; Poliquin, Eric; Caron, Mario; Wong, Kerwin; Shukri, Ziad; Martin, Jean-Pierre

    2000-04-01

    The purpose of this paper is to analyze the image quality of a selenium-based flat panel detector suited for digital interventional mammography. To characterize the image quality, the DQE was measured at various x-ray exposures. The results indicate that when the detector is quantum noise limited, the DQE is independent of the exposure. A measurement of the quantum detection efficiency of 90% indicates that an electrostatic field shaping effect within the selenium layer gives a greater collection efficiency than that predicted simply by the geometric fill factor of each pixel collection electrode. Measurements were also conducted to determine the relative strength of ghost images on the detector. An image of a high contrast object using an exposure of 183 mR was acquired, followed by a low exposure 6 mR flat field image. No visual indication of a ghost could be found in the latter image even after appropriate windowing and leveling of the image was performed. A subjective comparison of image quality between film/screen and the detector was conducted by acquiring images of the ACR phantom under various exposure conditions. The digital images were printed on film using optimally adjusted LUT's. The resulting images were randomly presented to 15 non-trained observers, who assessed a score for each image. The comparison results show that the image quality obtained with the digital detector is superior to the images acquired with film/screen.

  2. Performance of advanced a-Si/CsI-based flat-panel x-ray detectors for mammography

    NASA Astrophysics Data System (ADS)

    Albagli, Douglas; Hudspeth, Heather; Possin, George E.; Lee, Ji Ung; Granfors, Paul R.; Giambattista, Brian W.

    2003-06-01

    The GE Senographe 2000D, the first full field digital mammography system based on amorphous Silicon (a-Si) flat panel arrays and a Cesium-Iodide (CsI) scintillator, has been in clinical use for several years. The purpose of this paper is to demonstrate and quantify improvements in the detective quantum efficiency (DQE) for both typical screening and ultra-low exposure levels for this technology platform. A new figure of merit, the electronic noise factor, is introduced to explicitly quantify the influence of the electronic noise, conversion factor, modulation transfer function (MTF), and pixel pitch towards the reduction of DQE at low exposure levels. Methods to improve the DQE through an optimization of both the flat panel design and the scintillator deposition process are discussed. The results show a substantial improvement in the DQE(f) at all frequencies and demonstrate the potential for DQE(0) to exceed 80%. The combination of high DQE at ultra low exposures and the inherent fast read-out capability makes this technology platform ideal for both current clinical procedures and advanced applications that may use multiple projections (tomosynthesis) or contrast media to enhance digital mammography.

  3. Artificial Neural Networks in Mammography Interpretation and Diagnostic Decision Making

    PubMed Central

    Burnside, Elizabeth S.

    2013-01-01

    Screening mammography is the most effective means for early detection of breast cancer. Although general rules for discriminating malignant and benign lesions exist, radiologists are unable to perfectly detect and classify all lesions as malignant and benign, for many reasons which include, but are not limited to, overlap of features that distinguish malignancy, difficulty in estimating disease risk, and variability in recommended management. When predictive variables are numerous and interact, ad hoc decision making strategies based on experience and memory may lead to systematic errors and variability in practice. The integration of computer models to help radiologists increase the accuracy of mammography examinations in diagnostic decision making has gained increasing attention in the last two decades. In this study, we provide an overview of one of the most commonly used models, artificial neural networks (ANNs), in mammography interpretation and diagnostic decision making and discuss important features in mammography interpretation. We conclude by discussing several common limitations of existing research on ANN-based detection and diagnostic models and provide possible future research directions. PMID:23781276

  4. An equivalent relative utility metric for evaluating screening mammography.

    PubMed

    Abbey, Craig K; Eckstein, Miguel P; Boone, John M

    2010-01-01

    Comparative studies of performance in screening mammography are often ambiguous. A new method will frequently show a higher sensitivity or detection rate than an existing standard with a concomitant increase in false positives or recalls. The authors propose an equivalent relative utility (ERU) metric based on signal detection theory to quantify screening performance in such comparisons. The metric is defined as the relative utility, as defined in classical signal detection theory, needed to make 2 systems equivalent. ERU avoids the problem of requiring a predefined putative relative utility, which has limited application of utility theory in receiver operating characteristic analysis. The metric can be readily estimated from recall and detection rates commonly reported in comparative clinical studies. An important practical advantage of ERU is that in prevalence matched populations, the measure can be estimated without an independent estimate of disease prevalence. Thus estimating ERU does not require a study with long-term follow-up to find cases of missed disease. The approach is applicable to any comparative screening study that reports results in terms of recall and detection rates, although the authors focus exclusively on screening mammography in this work. They derive the ERU from the definition of utility given in classical treatments of signal detection theory. They also investigate reasonable values of relative utility in screening mammography for use in interpreting ERU using data from a large clinical study. As examples of application of ERU, they reanalyze 2 recently published reports using recall and detection rates in screening mammography.

  5. Impact of screening mammography on breast cancer mortality.

    PubMed

    Bleyer, Archie; Baines, Cornelia; Miller, Anthony B

    2016-04-15

    The degree to which observed reductions in breast cancer mortality is attributable to screening mammography has become increasingly controversial. We examined this issue with three fundamentally different approaches: (i) Chronology--the temporal relationship of the onset of breast cancer mortality decline and the national implementation of screening mammography; (ii) Magnitude--the degree to which breast cancer mortality declined relative to the amount (penetration) of screening mammography; (iii) Analogy--the pattern of mortality rate reductions of other cancers for which population screening is not conducted. Chronology and magnitude were assessed with data from Europe and North America, with three methods applied to magnitude. A comparison of eight countries in Europe and North America does not demonstrate a correlation between the penetration of national screening and either the chronology or magnitude of national breast cancer mortality reduction. In the United States, the magnitude of the mortality decline is greater in the unscreened, younger women than in the screened population and regional variation in the rate of breast cancer mortality reduction is not correlated with screening penetrance, either as self-reported or by the magnitude of screening-induced increase in early-stage disease. Analogy analysis of United States data identifies 14 other cancers with a similar distinct onset of mortality reduction for which screening is not performed. These five lines of evidence from three different approaches and additional observations discussed do not support the hypothesis that mammography screening is a primary reason for the breast cancer mortality reduction in Europe and North America.

  6. Small field detector correction factors: effects of the flattening filter for Elekta and Varian linear accelerators.

    PubMed

    Tyler, Madelaine K; Liu, Paul Z Y; Lee, Christopher; McKenzie, David R; Suchowerska, Natalka

    2016-05-08

    Flattening filter-free (FFF) beams are becoming the preferred beam type for stereotactic radiosurgery (SRS) and stereotactic ablative radiation therapy (SABR), as they enable an increase in dose rate and a decrease in treatment time. This work assesses the effects of the flattening filter on small field output factors for 6 MV beams generated by both Elekta and Varian linear accelerators, and determines differences between detector response in flattened (FF) and FFF beams. Relative output factors were measured with a range of detectors (diodes, ionization cham-bers, radiochromic film, and microDiamond) and referenced to the relative output factors measured with an air core fiber optic dosimeter (FOD), a scintillation dosimeter developed at Chris O'Brien Lifehouse, Sydney. Small field correction factors were generated for both FF and FFF beams. Diode measured detector response was compared with a recently published mathematical relation to predict diode response corrections in small fields. The effect of flattening filter removal on detector response was quantified using a ratio of relative detector responses in FFF and FF fields for the same field size. The removal of the flattening filter was found to have a small but measurable effect on ionization chamber response with maximum deviations of less than ± 0.9% across all field sizes measured. Solid-state detectors showed an increased dependence on the flattening filter of up to ± 1.6%. Measured diode response was within ± 1.1% of the published mathematical relation for all fields up to 30 mm, independent of linac type and presence or absence of a flattening filter. For 6 MV beams, detector correction factors between FFF and FF beams are interchangeable for a linac between FF and FFF modes, providing that an additional uncertainty of up to ± 1.6% is accepted.

  7. Application of a radiophotoluminescent glass plate dosimeter for small field dosimetry.

    PubMed

    Aaki, Fujio; Ishidoya, Tatsuya; Ikegami, Tohru; Moribe, Nobuyuki; Yamashita, Yasuyuki

    2005-06-01

    We have recently developed a prototypical radiophotoluminescent glass plate dosimeter (GPD) system as a device for small field dosimetry. The purpose of this study is to examine the usefulness of the GPD system for small field dosimetry. The profiles measured with the GPD were evaluated by comparing them to those from Kodak X-Omat V and GAFCROMIC XR type R film dosimeters for 2, 5, 9, and 15 mm circular collimators created by a linear accelerator-based radiosurgery system. The GPD output factors were compared with those of various detectors including an ion chamber, a p-type silicon diode detector, a glass rod dosimeter (GRD), and a diamond detector. The results measured with the GPD were also confirmed by comparing them to those from Monte Carlo simulations. The accuracy of a simulated beam is validated by the excellent agreement between Monte Carlo calculated and measured central axis depth-dose curves for 9- and 15 mm circular collimators using 4- and 10 MV photon beams. The GPD profiles show almost the same full width at half maximum as those of film dosimeters and Monte Carlo simulations at 4- and 10 MV photon beams, but a little narrower penumbrae than the film dosimeters and Monte Carlo simulations. The output factors measured with the GPD are in good agreement with those from a diode detector, a diamond detector, and the GRD with a small active volume and Monte Carlo simulations, except for a very small 2 mm circular collimator. It was found that the GPD is a very useful detector for small field dosimetry.

  8. A robust procedure for verifying TomoTherapy Hi-Art™ source models for small fields

    NASA Astrophysics Data System (ADS)

    Hundertmark, B.; Sterpin, E.; Mackie, T.

    2011-06-01

    The dosimetric measurement and modeling of small radiation treatment fields (<2 × 2 cm2) are difficult to perform and prone to error. Measurements of small fields are often adversely influenced by the properties of the detectors used to make them. The dosimetric properties of small fields have been difficult to accurately model due to the effects of source occlusion caused by the collimating jaws. In this study, small longitudinal slice widths (SWs) of the TomoTherapy® Hi-Art® machine are characterized by performing dosimetric measurements topographically. By using a static gantry, opening the central 16 MLC leaves during the irradiations, and symmetrically scanning detectors 10 cm through each longitudinal SW, integral doses to a 'TomoTherapy equivalent' 10 × 10 cm2 area are topographically measured. To quantify the effects of source occlusion for TomoTherapy, a quantity referred to as the integral scanned dose to slice width ratio (D/SW) is introduced. (D/SW) ratios are measured for SWs ranging from 0.375 to 5 cm in size using ion chambers and a radiographic film. The measurements of the (D/SW) ratio are shown to be insensitive to the detectors used in this study. The (D/SW) ratios for TomoTherapy have values of unity in the range of SW sizes from 5 cm to approximately 2 cm. For SWs smaller than 2 cm in size, the source-occlusion effect substantially reduces the measured machine output and the value of the (D/SW) ratios. The topographic measurement method presented provides a way to directly evaluate the accuracy of the small-field source model parameters used in dose calculation algorithms. As an example, the electron source spot size of a Penelope Monte Carlo (MC) model of TomoTherapy was varied to match computed and measured (D/SW) ratios. It was shown that the MC results for small SW sizes were sensitive to that particular parameter.

  9. Optimization and Comparison of Different Digital Mammographic Tomosynthesis Reconstruction Methods

    DTIC Science & Technology

    2007-04-01

    likelihood iterative algorithm (MLEM) by Wu et al. [4,5], tuned-aperture computed tomography (TACT) reconstruction methods developed by Webber and...A. Karellas, S. Vedantham, S. J. Glick, C. J. D’Orsi, S. P. Baker, and R. L. Webber , “Comparison of tomosynthesis methods used with digital...L. Webber , “Evaluation of linear and nonlinear tomosynthetic reconstruction methods in digital mammography,” Acad. Radiol. 8, 219-224 (2001). 8. L

  10. Radiologists' interpretive efficiency and variability in true- and false-positive detection when screen-reading with tomosynthesis (3D-mammography) relative to standard mammography in population screening.

    PubMed

    Svahn, Tony M; Macaskill, Petra; Houssami, Nehmat

    2015-12-01

    We examined interpretive efficiency and variability in true- and false-positive detection (TP, FP) for radiologists screen-reading with digital breast tomosynthesis as adjunct to full-field digital mammography (2D/3D) relative to 2D alone in population-based screening studies. A systematic literature search was performed to identify screening studies that provided radiologist-specific data for TP and FP detection. Radiologist interpretive efficiency (trade-off between TPs and FPs) was calculated using the FP:TP ratio which expresses the number of FP recalls for each screen-detected breast cancer. We modeled a pooled FP:TP ratio to assess variability in radiologists' interpretive efficiency at study-level using random effects logistic regression. FP:TP ratio improved (ratio decreased) for 2D/3D screen-reading (relative to 2D) for a majority of radiologists (18 of 22) across all studies. Variability in radiologists' FP:TP ratio was consistently lower in all studies for 2D/3D screen-reading, as suggested by lower variance in ratios. Study-level pooled FP:TP ratio for 2D- and 2D/3D-mammography respectively, were 5.96 (95%CI: 4.08 to 8.72) and 3.17 (95%CI: 2.25 to 4.47) for the STORM trial; 10.25 (95%CI: 6.42 to 16.35) and 7.07 (95%CI: 4.99 to 10.02) for the Oslo trial; and 20.84 (95%CI: 13.95 to 31.12) and 8.37 (95%CI: 5.87 to 11.93) for the Houston study. This transfers into study-level improved interpretative efficiencies of 48%, 30% and 55%, respectively, for 2D/3D screen-reading (relative to 2D). In summary, study-level FP:TP trade-off improved using 2D/3D-mammography for all studies, which was also seen for most individual radiologists. There was variability in the FP:TP trade-off between readers and studies for 2D-as well as for 2D/3D-interpretations but variability in radiologists' interpretive efficiency was relatively lower using 2D/3D-mammography.

  11. SU-E-T-323: Dosimetric Evaluation of Small Fields for SBRT Treatment

    SciTech Connect

    Gupta, R; Eldib, A; Wang, B; Ma, C; Li, J

    2015-06-15

    Purpose: Stereotactic body radiation therapy (SBRT) is commonly employed to treat small targets for effective tumor control with radiation beams of small field sizes. The goal of this work was to evaluate dosimetrically a treatment planning system (TPS) by comparing the calculated dose for SBRT treatment with ion-chamber measurements. Methods: 3D images of a solid-water phantom with a pinpoint ion-chamber (0.015cm3) inside were acquired with a CT scanner. Active volume of the ion-chamber was delineated on CT images. Targets with a diameter of 1.5cm, 2cm, 3cm, 4cm and 5cm were drawn around the chamber. 3DCRT plans were generated for each target size with centrally opened 6MV beams and off-axis beams by changing the isocenter location, respectively, using a TPS with the Analytical Anisotropic Algorithm. A 21iX linear accelerator was employed for plan delivery. The measured and calculated doses were compared. To evaluate the dose calculations in heterogeneity for small fields SBRT treatment, similar plans were also generated and delivered on a heterogeneous thoracic phantom for 5 different size targets in the lung. Results: Dose comparisons between measurements and calculations showed 5.2%, 1.88%, 1.34%, 1.01% and 0.85% difference for SBRT plans with small central axis beams and 0.96%, 0.15%, 0.58%, 0.22% and 0.77% difference for plans with off-axis beams for five different size targets. For the thoracic phantom, the differences on dose between measurements and calculations are bigger, which are 8%, 5.9%, 4.5%, 3.9% and 4.5%, respectively. Conclusion: Dose verification for small fields used in the SBRT treatment has been performed based on ion-chamber measurements in both homogenous and heterogeneous phantoms. More than a 5% difference has been observed in the heterogeneous phantom, especially for very small fields. To meet the ICRU recommendation on a dose difference of no more than 5%, some corrections on the commissioning parameters of the TPS are needed.

  12. A scheme for assessing the performance characteristics of small field-of-view gamma cameras.

    PubMed

    Bhatia, B S; Bugby, S L; Lees, J E; Perkins, A C

    2015-02-01

    Existing protocols for assessing the performance characteristics of large field-of-view (LFOV) gamma cameras can be inappropriate and require modification for use with small field-of-view (SFOV) gamma camera systems. This communication proposes a generic scheme suitable for evaluating the performance characteristics of SFOV gamma cameras, based on modifications to the standard procedures of NEMA NU1-2007. Key differences in methodology between tests for LFOV and SFOV gamma cameras are highlighted along with the rationale for these changes. It is envisaged that this scheme will provide more appropriate methods for equipment characterisation, ensuring quality and consistency for all SFOV cameras.

  13. Breast Cancers Found with Digital Breast Tomosynthesis: A Comparison of Pathology and Histologic Grade.

    PubMed

    Wang, Wei-Shin; Hardesty, Lara; Borgstede, James; Takahashi, Jayme; Sams, Sharon

    2016-11-01

    To compare the pathology and histologic grading of breast cancers detected with digital breast tomosynthesis to those found with conventional digital mammography. The institutional review board approved this study. A database search for all breast cancers diagnosed from June 2012 through December 2013 was performed. Imaging records for these cancers were reviewed and patients who had screening mammography with tomosynthesis as their initial examination were selected. Five dedicated breast imaging radiologists reviewed each of these screening mammograms to determine whether the cancer was visible on conventional digital mammography or whether tomosynthesis was needed to identify the cancer. A cancer was considered mammographically occult if all five radiologists agreed that the cancer could not be seen on conventional digital mammography. The size, pathology and histologic grading for all diagnosed breast cancers were then reviewed. The Mann-Whitney U and Fisher exact tests were utilized to determine any association between imaging findings and cancer size, pathologic type and histologic grade. Sixty-five cancers in 63 patients were identified. Ten of these cancers were considered occult on conventional digital mammography and detected with the addition of tomosynthesis. These mammographically occult cancers were significantly associated with Nottingham grade 1 histologic pathology (p = 0.02), were smaller (median size: 6 mm versus 10 mm, p = 0.07) and none demonstrated axillary nodal metastases. Breast cancers identified through the addition of tomosynthesis are associated with Nottingham grade 1 histologic pathology and prognostically more favorable than cancers identified with conventional digital mammography alone.

  14. Postmortem validation of breast density using dual-energy mammography

    PubMed Central

    Molloi, Sabee; Ducote, Justin L.; Ding, Huanjun; Feig, Stephen A.

    2014-01-01

    Purpose: Mammographic density has been shown to be an indicator of breast cancer risk and also reduces the sensitivity of screening mammography. Currently, there is no accepted standard for measuring breast density. Dual energy mammography has been proposed as a technique for accurate measurement of breast density. The purpose of this study is to validate its accuracy in postmortem breasts and compare it with other existing techniques. Methods: Forty postmortem breasts were imaged using a dual energy mammography system. Glandular and adipose equivalent phantoms of uniform thickness were used to calibrate a dual energy basis decomposition algorithm. Dual energy decomposition was applied after scatter correction to calculate breast density. Breast density was also estimated using radiologist reader assessment, standard histogram thresholding and a fuzzy C-mean algorithm. Chemical analysis was used as the reference standard to assess the accuracy of different techniques to measure breast composition. Results: Breast density measurements using radiologist reader assessment, standard histogram thresholding, fuzzy C-mean algorithm, and dual energy were in good agreement with the measured fibroglandular volume fraction using chemical analysis. The standard error estimates using radiologist reader assessment, standard histogram thresholding, fuzzy C-mean, and dual energy were 9.9%, 8.6%, 7.2%, and 4.7%, respectively. Conclusions: The results indicate that dual energy mammography can be used to accurately measure breast density. The variability in breast density estimation using dual energy mammography was lower than reader assessment rankings, standard histogram thresholding, and fuzzy C-mean algorithm. Improved quantification of breast density is expected to further enhance its utility as a risk factor for breast cancer. PMID:25086548

  15. Postmortem validation of breast density using dual-energy mammography

    SciTech Connect

    Molloi, Sabee Ducote, Justin L.; Ding, Huanjun; Feig, Stephen A.

    2014-08-15

    Purpose: Mammographic density has been shown to be an indicator of breast cancer risk and also reduces the sensitivity of screening mammography. Currently, there is no accepted standard for measuring breast density. Dual energy mammography has been proposed as a technique for accurate measurement of breast density. The purpose of this study is to validate its accuracy in postmortem breasts and compare it with other existing techniques. Methods: Forty postmortem breasts were imaged using a dual energy mammography system. Glandular and adipose equivalent phantoms of uniform thickness were used to calibrate a dual energy basis decomposition algorithm. Dual energy decomposition was applied after scatter correction to calculate breast density. Breast density was also estimated using radiologist reader assessment, standard histogram thresholding and a fuzzy C-mean algorithm. Chemical analysis was used as the reference standard to assess the accuracy of different techniques to measure breast composition. Results: Breast density measurements using radiologist reader assessment, standard histogram thresholding, fuzzy C-mean algorithm, and dual energy were in good agreement with the measured fibroglandular volume fraction using chemical analysis. The standard error estimates using radiologist reader assessment, standard histogram thresholding, fuzzy C-mean, and dual energy were 9.9%, 8.6%, 7.2%, and 4.7%, respectively. Conclusions: The results indicate that dual energy mammography can be used to accurately measure breast density. The variability in breast density estimation using dual energy mammography was lower than reader assessment rankings, standard histogram thresholding, and fuzzy C-mean algorithm. Improved quantification of breast density is expected to further enhance its utility as a risk factor for breast cancer.

  16. [The attitude before subclinical breast lesions on mammography].

    PubMed

    Blidaru, A; Sebeni, M; Bordea, C; Viişoreanu, C; Bălănescu, I

    2000-01-01

    Mammographic screening and improvement of mammography resolution have resulted in the increasingly frequent identification of small-size mammary lesions that have no clinical expression. If in Western countries, approximately one quarter of breast cancers are discovered when clinically occult, in Romania such cases are rare and, most of the times, discovered merely by chance. Infraclinical mammary lesions identified by mammography pose problems concerning the appropriate response. The paper assesses the various diagnosis and therapy choices as well as the localization techniques to be employed in order to establish the best approach. We describe twelve cases of infraclinical mammary lesions identified by mammography. In two of this cases fine needle aspiration biopsy with cytological examination was used, and in one case we performed core biopsy and histological examination. In those cases, lesion localization has been performed using stereotactic X-ray devices. In nine cases, we performed excisional biopsy with histologic assessment. In four of those cases, the lesions proved to be malignant. Preoperative localization was performed with hookwires placed in the proximity of the lesion under mammographic control. In five of those cases, lesion coordinates have been determined by stereotaxy. Using this technique, we removed, in all cases, the clinical lesions identified by mammography. We believe surgical excision to be the best approach in such lesions. Total removal of the lesion enables a thorough histopathological examination resulting in more accurate diagnosis. Curative surgery is also possible within the same surgical procedure. Unless preoperative localization is performed the surgeon is in the position to excise an image that has no clinical expression. Under this circumstances surgical removal is performed blind, as the lesion is hard to be found even intraoperatory. Preoperative localization provides guidance to the surgeon, ensures removal of the lesion

  17. SU-D-304-03: Small Field Proton Dosimetry Using MicroDiamond and Gafchromic Film

    SciTech Connect

    Andersen, A; Das, I; Coutinho, L

    2015-06-15

    Purpose: Certain dosimetric characteristics continue to make proton beam therapy an appealing modality for cancer treatment. The proton Bragg peak allows for conformal radiation dose delivery to the target while reducing dose to normal tissue and organs. As field sizes become very small the benefit of the Bragg peak is diminished due to loss of transverse equilibrium along the central beam axis. Furthermore, aperture scattering contributes additional dose along the central axis. These factors warrant the need for accurate small field dosimetry. In this study small field dosimetry was performed using two different methods. Methods: Small field dosimetry measurements were performed using a PTW microdiamond detector and Gafchromic EBT2 film for aperture sizes ranging from 0.5cm to 10cm and a proton range in water of 10cm to 27cm. The measurements were analyzed and then compared to each other and to reference dosimetry data acquired with a Markus chamber. Results: A decrease in normalized output is observed at small field sizes and at larger ranges in water using both measurement methods. Also, a large variation is observed between the output measurements by microdiamond and film at very small field sizes. At the smallest aperture, normalized output ranged from 0.16 to 0.72 and the percent difference between both measurement methods ranged from 36% to 70% depending on proton range. At field sizes above 5cm the film and microdiamond agree within 3%. Conclusion: Although both measurement methods exhibit a general decrease in output factor at small field sizes, dosimetric measurements for small fields using these two methods can vary significantly. Dosimetry under standard conditions is not sufficient to correctly model the dose distributions and outputs factors for small field sizes, additional small field measurements should be performed.

  18. The practical application of scintillation dosimetry in small-field photon-beam radiotherapy.

    PubMed

    Burke, Elisa; Poppinga, Daniela; Schönfeld, Andreas A; Harder, Dietrich; Poppe, Björn; Looe, Hui Khee

    2017-03-22

    Plastic scintillation detectors are a new instrument of stereotactic photon-beam dosimetry. The clinical application of the plastic scintillation detector Exradin W1 at the Siemens Artiste and Elekta Synergy accelerators is a matter of current interest. In order to reduce the measurement uncertainty, precautions have to be taken with regard to the geometrical arrangement of the scintillator, the light-guide fiber and the photodiode in the radiation field. To determine the "Cerenkov light ratio" CLR with a type A uncertainty below 1%, the Cerenkov calibration procedure for small-field measurements based on the two-channel spectral method was used. Output factors were correctly measured with the W1 for field sizes down to 0.5×0.5cm(2) with a type A uncertainty of 1.8%. Measurements of small field dose profiles and percentage depth dose curves were carried out with the W1 using automated water phantom profile scans, and a type A uncertainty for dose maxima of 1.4% was achieved. The agreement with a synthetic diamond detector (microDiamond, PTW Freiburg) and a plane parallel ionization chamber (Roos chamber, PTW Freiburg) in relative dose measurements was excellent. In oversight of all results, the suitability of the plastic scintillation detector Exradin W1 for clinical dosimetry under stereotactic conditions, in particular the tried and tested procedures for CLR determination, output factor measurement and automated dose profile scans in water phantoms, have been confirmed.

  19. Three-dimensional magnetic nanoparticle imaging using small field gradient and multiple pickup coils

    NASA Astrophysics Data System (ADS)

    Sasayama, Teruyoshi; Tsujita, Yuya; Morishita, Manabu; Muta, Masahiro; Yoshida, Takashi; Enpuku, Keiji

    2017-04-01

    We propose a magnetic particle imaging (MPI) method based on third harmonic signal detection using a small field gradient and multiple pickup coils. First, we developed a system using two pickup coils and performed three-dimensional detection of two magnetic nanoparticle (MNP) samples, which were spaced 15 mm apart. In the experiments, an excitation field strength of 1.6 mT was used at an operating frequency of 3 kHz. A DC gradient field with a typical value of 0.2 T/m was also used to produce the so-called field-free line. A third harmonic signal generated by the MNP samples was detected using the two pickup coils, and the samples were then mechanically scanned to obtain field maps. The field maps were subsequently analyzed using the nonnegative least squares method to obtain three-dimensional position information for the MNP samples. The results show that the positions of the two MNP samples were estimated with good accuracy, despite the small field gradient used. Further improvement in MPI performance will be achieved by increasing the number of pickup coils used.

  20. Small-Field Measurements of 3D Polymer Gel Dosimeters through Optical Computed Tomography

    PubMed Central

    Shih, Cheng-Ting; Lee, Yao-Ting; Wu, Shin-Hua; Yao, Chun-Hsu; Hsieh, Bor-Tsung

    2016-01-01

    With advances in therapeutic instruments and techniques, three-dimensional dose delivery has been widely used in radiotherapy. The verification of dose distribution in a small field becomes critical because of the obvious dose gradient within the field. The study investigates the dose distributions of various field sizes by using NIPAM polymer gel dosimeter. The dosimeter consists of 5% gelatin, 5% monomers, 3% cross linkers, and 5 mM THPC. After irradiation, a 24 to 96 hour delay was applied, and the gel dosimeters were read by a cone beam optical computed tomography (optical CT) scanner. The dose distributions measured by the NIPAM gel dosimeter were compared to the outputs of the treatment planning system using gamma evaluation. For the criteria of 3%/3 mm, the pass rates for 5 × 5, 3 × 3, 2 × 2, 1 × 1, and 0.5 × 0.5 cm2 were as high as 91.7%, 90.7%, 88.2%, 74.8%, and 37.3%, respectively. For the criteria of 5%/5 mm, the gamma pass rates of the 5 × 5, 3 × 3, and 2 × 2 cm2 fields were over 99%. The NIPAM gel dosimeter provides high chemical stability. With cone-beam optical CT readouts, the NIPAM polymer gel dosimeter has potential for clinical dose verification of small-field irradiation. PMID:26974434

  1. MO-AB-207-00: ACR Update in MR, CT, Nuclear Medicine, and Mammography

    SciTech Connect

    2015-06-15

    A goal of an imaging accreditation program is to ensure adequate image quality, verify appropriate staff qualifications, and to assure patient and personnel safety. Currently, more than 35,000 facilities in 10 modalities have been accredited by the American College of Radiology (ACR), making the ACR program one of the most prolific accreditation options in the U.S. In addition, ACR is one of the accepted accreditations required by some state laws, CMS/MIPPA insurance and others. Familiarity with the ACR accreditation process is therefore essential to clinical diagnostic medical physicists. Maintaining sufficient knowledge of the ACR program must include keeping up-to-date as the various modality requirements are refined to better serve the goals of the program and to accommodate newer technologies and practices. This session consists of presentations from authorities in four ACR accreditation modality programs, including magnetic resonance imaging, computed tomography, nuclear medicine, and mammography. Each speaker will discuss the general components of the modality program and address any recent changes to the requirements. Learning Objectives: To understand the requirements of the ACR MR Accreditation program. The discussion will include accreditation of whole-body general purpose magnets, dedicated extremity systems well as breast MRI accreditation. Anticipated updates to the ACR MRI Quality Control Manual will also be reviewed. To understand the requirements of the ACR CT accreditation program, including updates to the QC manual as well as updates through the FAQ process. To understand the requirements of the ACR nuclear medicine accreditation program, and the role of the physicist in annual equipment surveys and the set up and supervision of the routine QC program. To understand the current ACR MAP Accreditation requirement and present the concepts and structure of the forthcoming ACR Digital Mammography QC Manual and Program.

  2. TU-A-18C-01: ACR Accreditation Updates in CT, Ultrasound, Mammography and MRI

    SciTech Connect

    Price, R; Berns, E; Hangiandreou, N; McNitt-Gray, M

    2014-06-15

    A goal of an imaging accreditation program is to ensure adequate image quality, verify appropriate staff qualifications, and to assure patient and personnel safety. Currently, more than 35,000 facilities in 10 modalities have been accredited by the American College of Radiology (ACR), making the ACR program one of the most prolific accreditation options in the U.S. In addition, the ACR is one of the accepted accreditations required by some state laws, CMS/MIPPA insurance and others. Familiarity with the ACR accreditation process is therefore essential to clinical diagnostic medical physicists. Maintaining sufficient knowledge of the ACR program must include keeping up-to-date as the various modality requirements are refined to better serve the goals of the program and to accommodate newer technologies and practices. This session consists of presentations from authorities in four ACR accreditation modality programs, including magnetic resonance imaging, mammography, ultrasound, and computed tomography. Each speaker will discuss the general components of the modality program and address any recent changes to the requirements. Learning Objectives: To understand the requirements of the ACR MR accreditation program. The discussion will include accreditation of whole-body general purpose magnets, dedicated extremity systems well as breast MRI accreditation. Anticipated updates to the ACR MRI Quality Control Manual will also be reviewed. To understand the current ACR MAP Accreditation requirement and present the concepts and structure of the forthcoming ACR Digital Mammography QC Manual and Program. To understand the new requirements of the ACR ultrasound accreditation program, and roles the physicist can play in annual equipment surveys and setting up and supervising the routine QC program. To understand the requirements of the ACR CT accreditation program, including updates to the QC manual as well as updates through the FAQ process.

  3. [Digital breast tomosynthesis : technical principles, current clinical relevance and future perspectives].

    PubMed

    Hellerhoff, K

    2010-11-01

    In recent years digital full field mammography has increasingly replaced conventional film mammography. High quality imaging is guaranteed by high quantum efficiency and very good contrast resolution with optimized dosing even for women with dense glandular tissue. However, digital mammography remains a projection procedure by which overlapping tissue limits the detectability of subtle alterations. Tomosynthesis is a procedure developed from digital mammography for slice examination of breasts which eliminates the effects of overlapping tissue and allows 3D imaging of breasts. A curved movement of the X-ray tube during scanning allows the acquisition of many 2D images from different angles. Subseqently, reconstruction algorithms employing a shift and add method improve the recognition of details at a defined level and at the same time eliminate smear artefacts due to overlapping structures. The total dose corresponds to that of conventional mammography imaging. The technical procedure, including the number of levels, suitable anodes/filter combinations, angle regions of images and selection of reconstruction algorithms, is presently undergoing optimization. Previous studies on the clinical value of tomosynthesis have examined screening parameters, such as recall rate and detection rate as well as information on tumor extent for histologically proven breast tumors. More advanced techniques, such as contrast medium-enhanced tomosynthesis, are presently under development and dual-energy imaging is of particular importance.

  4. TU-F-BRE-05: Experimental Determination of K Factor in Small Field Dosimetry

    SciTech Connect

    Das, I; Akino, Y; Francescon, P

    2014-06-15

    Purpose: Small-field dosimetry is challenging due to charged-particle disequilibrium, source occlusion and more importantly finite size of detectors. IAEA/AAPM has published approach to convert detector readings to dose by k factor. Manufacturers have been trying to provide various types of micro-detectors that could be used in small fields. However k factors depends on detector perturbations and are derived using Monte Carlo simulation. PTW has introduced a microDiamond for small-field dosimetry. An experimental approach is presented to derive the k factor for this detector. Methods: PTW microDiamond is a small volume detector with 1.1 mm radius and 1.0 micron thick synthetic diamond. Output factors were measured from 1×1cm2 to 12×12 cm2 on a Varian machine at various depths using various micro-detectors with published k factors. Dose is calculated as reading * K. Assuming k factor is accurate, output factor should be identical with every micro-detectors. Hence published k values (Francescon et al Med Phys 35, 504-513,2008) were used to covert readings and then output factors were computed. Based on the converged curve from other detectors, k factor for microDiamond was computed versus field size. Results: Traditional output factors as ratio of readings normalized to 10×10 cm2 differ significantly for micro-detectors for fields smaller than 3×3 cm2 which are now being used extensively. When readings are converted to dose, the output factor is independent of detector. Based on this method, k factor for microDiamond was estimated to be nearly constant 0.993±0.007 over varied field sizes. Conclusion: Our method provides a unique opportunity to determine the k factor for any unknown detector. It is shown that even though k factor depends on machine type due to focal spot, however for fields ≥1×1 cm2 this method provides accurate evaluation of k factor. Additionally microDiamond could be used with assumption that k factor is nearly unity.

  5. MO-D-BRD-02: In Memoriam of Bengt Bjarngard: SBRT II: Small Field Dosimetry - TG155

    SciTech Connect

    Das, I; Reft, C

    2014-06-15

    Specialized radiation treatment such as SRS/SRT. SBRT, IMRT, VMAT, Tomotherapy, CyberKnife and Gamma Knife use small fields or combination of small fields where dosimetry is challenging and uncertain due to non-equilibrium conditions such as longitudinal and lateral disequilibrium. Additionally the primary photon fluence is greatly affected by the obstruction of the source size by the jaws creating a large dose gradient across the field. Electronic equilibrium is a phenomenon associated with the range of secondary particles which depend on the beam energy, photon spectrum and the composition of the medium. Additionally, the finite size of detectors creates volume averaging and fluence perturbations especially in small fields. The IAEA/AAPM has provided a frame work for non-compliant reference dosimetry in small fields1. The AAPM TG-1552 has adopted this frame work to provide guidelines in relative dosimetry. This course provides the insight of TG-155 that defines small field, provides recommendations for suitable detectors and associated correction factors to convert reading to dose. Recommendations of a good working practice for relative dosimetry measurements (PDD, TMR, output factor, etc.) and dose calculations based on the new formulation is are elaborated. It also discusses beam modeling and dose calculations as a critical step in clinical utilization of small field radiotherapy. Small errors in beam data, approximations in dose algorithms, or misaligned of detectors and field settings can propagate into large errors in planned and delivered dose. The modeling and treatment planning aspects of small field dosimetry are reviewed with emphasis on the most critical parts for ensuring accurate and safe radiation therapy. Discussion on k(fmsr, fclin) for commercially available detectors are also provided.1 P. Alfonso, P. Andreo, R. Capote, M. S. Huq, W. Kilby, P. Kjall, T. R. Mackie, H. Palmans, K. Rosser, J. Seuntjens, W. Ullrich and S. Vatnitsky, “A new

  6. [Digital noninvasive microwave thermography in the diagnosis of breast disease].

    PubMed

    Fan, K H; Fan, J H; Yao, D D; Jin, W D; Yang, B G; Meng, C X; Qu, D B

    1988-05-01

    Thermography is a noninvasive technic of examination. Liquid-Crystal Thermography and Infrared Thermography have provided great help in the general survey of breast diseases during the past twenty years but not without some limitations. Recently, by applying the microwave technic clinically, progress has been made to measure minute temperature changes in the deeper tissues. Differential diagnosis of breast disease is possible by statistical calculating the temperature difference of the two breasts. A prospective study was done in 96 women who had both X ray mammography and digital noninvasive microwave thermography. 70/96 were proved by pathology. In this group of patients, the accuracy rate was 70.00% for digital microwave thermography, 81.82% for X ray mammography and 95.50% for the two combined. The false positive rates and false negative rates, advantages, disadvantages and the for general survey of breast disease of the digital microwave thermography discussed.

  7. Evaluation of beam modeling for small fields using a flattening filter-free beam.

    PubMed

    Kawahara, Daisuke; Ozawa, Shuichi; Nakashima, Takeo; Aita, Masamichi; Tsuda, Shintaro; Ochi, Yusuke; Okumura, Takuro; Masuda, Hirokazu; Ohno, Yoshimi; Murakami, Yuji; Nagata, Yasushi

    2017-03-01

    The characteristics of a flattening filter-free (FFF) beam are different from those of a beam with a flattening filter. For small-field dosimetry, the beam data needed by the radiation treatment planning system (RTPS) includes the percent depth dose (PDD), off-center ratio (OCR), and output factor (OPF) for field sizes down to 3 × 3 cm(2) to calculate the beam model. The purpose of this study was to evaluate the accuracy of calculations for the FFF beam by the Eclipse(™) treatment planning system for field sizes smaller than 3 × 3 cm(2) (2 × 2 and 1 × 1 cm(2)). We used 6X and 10X FFF beams by the Varian TrueBeam(™) to produce. The AAA and AXB algorithms of the Eclipse were used to compare the Monte Carlo (MC) calculation and the measurements from three dosimeters, a diode detector, a PinPoint dosimeter, and EBT3 film. The PDD curves and the penumbra width in the OCR calculated by the Eclipse, measured data, and those from the MC calculations were in good agreement to within ±2.8 % and ±0.6 mm, respectively. However, the difference in the OPF values between AAA and AXB for a field size of 1 × 1 cm(2) was 5.3 % for the 6X FFF beam and 7.6 % for the 10X FFF beam. Therefore, we have to confirm the small field data that is included for the RTPS commission procedures.

  8. Mammography: an update of the EUSOBI recommendations on information for women.

    PubMed

    Sardanelli, Francesco; Fallenberg, Eva M; Clauser, Paola; Trimboli, Rubina M; Camps-Herrero, Julia; Helbich, Thomas H; Forrai, Gabor

    2017-02-01

    This article summarises the information to be offered to women about mammography. After a delineation of the aim of early diagnosis of breast cancer, the difference between screening mammography and diagnostic mammography is explained. The need to bring images and reports from the previous mammogram (and from other recent breast imaging examinations) is highlighted. Mammography technique and procedure are described with particular attention to discomfort and pain experienced by a small number of women who undergo the test. Information is given on the recall during a screening programme and on the request for further work-up after a diagnostic mammography. The logic of the mammography report and of classification systems such as R1-R5 and BI-RADS is illustrated, and brief but clear information is given about the diagnostic performance of the test, with particular reference to interval cancers, i.e., those cancers that are missed at screening mammography. Moreover, the breast cancer risk due to radiation exposure from mammography is compared to the reduction in mortality obtained with the test, and the concept of overdiagnosis is presented with a reliable estimation of its extent. Information about new mammographic technologies (tomosynthesis and contrast-enhanced spectral mammography) is also given. Finally, frequently asked questions are answered.

  9. Mammography X-Ray Spectra Simulated with Monte Carlo

    SciTech Connect

    Vega-Carrillo, H. R.; Gonzalez, J. Ramirez; Manzanares-Acuna, E.; Hernandez-Davila, V. M.; Villasana, R. Hernandez; Mercado, G. A.

    2008-08-11

    Monte Carlo calculations have been carried out to obtain the x-ray spectra of various target-filter combinations for a mammography unit. Mammography is widely used to diagnose breast cancer. Further to Mo target with Mo filter combination, Rh/Rh, Mo/Rh, Mo/Al, Rh/Al, and W/Rh are also utilized. In this work Monte Carlo calculations, using MCNP 4C code, were carried out to estimate the x-ray spectra produced when a beam of 28 keV electrons did collide with Mo, Rh and W targets. Resulting x-ray spectra show characteristic x-rays and continuous bremsstrahlung. Spectra were also calculated including filters.

  10. An SVM Based Approach for the Analysis Of Mammography Images

    NASA Astrophysics Data System (ADS)

    Gan, X.; Kapsokalivas, L.; Skaliotis, A.; Steinhöfel, K.; Tangaro, S.

    2007-09-01

    Mammography is among the most popular imaging techniques used in the diagnosis of breast cancer. Nevertheless distinguishing between healthy and ill images is hard even for an experienced radiologist, because a single image usually includes several regions of interest (ROIs). The hardness of this classification problem along with the substantial amount of data, gathered from patients' medical history, motivates the use of a machine learning approach as part of a CAD (Computer Aided Detection) tool, aiming to assist radiologists in the characterization of mammography images. Specifically, our approach involves: i) the ROI extraction, ii) the Feature Vector extraction, iii) the Support Vector Machine (SVM) classification of ROIs and iv) the characterization of the whole image. We evaluate the performance of our approach in terms of the SVM's training and testing error and in terms of ROI specificity—sensitivity. The results show a relation between the number of features used and the SVM's performance.

  11. Nonlinear Elasto-Mammography for Characterization of Breast Tissue Properties

    PubMed Central

    Wang, Z. G.; Liu, Y.; Wang, G.; Sun, L. Z.

    2011-01-01

    Quantification of the mechanical behavior of normal and cancerous tissues has important implication in the diagnosis of breast tumor. The present work extends the authors' nonlinear elastography framework to incorporate the conventional X-ray mammography, where the projection of displacement information is acquired instead of full three-dimensional (3D) vector. The elastic parameters of normal and cancerous breast tissues are identified by minimizing the difference between the measurement and the corresponding computational prediction. An adjoint method is derived to calculate the gradient of the objective function. Simulations are conducted on a 3D breast phantom consisting of the fatty tissue, glandular tissue, and cancerous tumor, whose mechanical responses are hyperelastic in nature. The material parameters are identified with consideration of measurement error. The results demonstrate that the projective displacements acquired in X-ray mammography provide sufficient constitutive information of the tumor and prove the usability and robustness of the proposed method and algorithm. PMID:22235197

  12. Characteristics of YouTube™ Videos Related to Mammography.

    PubMed

    Basch, Corey H; Hillyer, Grace Clarke; MacDonald, Zerlina L; Reeves, Rachel; Basch, Charles E

    2015-12-01

    With a monthly total of more than one billion unique visitors, YouTube™ is one of the Internet's most visited websites and contributes to the growing amount of health-related information on the Internet. The purpose of this study was to analyze coverage of mammography screening in popular YouTube™ videos. A total of 173 videos were included in the analysis. Compared with professionally created videos, consumer-created videos had a significantly greater number of comments (>9 comments 38.0% for consumer vs. 11.8% for professional videos, p=<0.001). Videos created by professionals more often portrayed general mammography information (97.1 vs. 88.7%) compared to those created by consumers. The vast majority of videos presented general information (93.6%) related to mammography, and almost two thirds addressed preparing for the test. Less than 20% dealt with other types of examinations. Approximately 30% discussed pain associated with the examination (35.3%) and addressed issues of anxiety (32.4%) and fear (29.5%). Nearly half of the videos presented information about the test results (46.2%). Over 25% covered medical or family history. The majority did not pertain to a specific age group. Future research should focus on analyzing the accuracy of the information in the videos.

  13. Hidden costs of mobile mammography: is subsidization necessary?

    PubMed

    Wolk, R B

    1992-06-01

    Two major impediments to an effective mammography program are inaccessibility and cost. This article itemizes the expenses associated with providing a mobile screening program accredited by the American College of Radiology (ACR) during a 3-year period. Mobile Diagnostics Inc. established a mobile mammography service in April 1987. A 36-ft (11-m) van is staffed by two registered technologists. The unit includes on-board processing and educational videotapes. Analysis of expenses for the years 1988, 1989, and 1990 does not include interpretation fees. A total of 3522 patients were examined in 1988, 4232 in 1989, and 5005 in 1990. Fixed operating expenses in 1988 were $70/examination and variable expenses were $13/examination, resulting in an average total cost per examination of $83. Fixed costs in 1989 were $63, variable costs were $15, and total costs were $78 per examination. Fixed costs in 1990 were $55, variable costs were $14, and total costs were $69 per examination. Many third parties, including Medicare, are contemplating a global screening fee in the $50-$60 range. An average payment of $55 would require examination of more than 6500 patients a year or 28 patients a day to break even. Our experience suggests that some form of subsidization may be necessary to sustain a mobile mammography service at those reimbursement levels.

  14. Behavioral Constructs and Mammography in Five Ethnic Groups

    PubMed Central

    Stewart, Susan L.; Rakowski, William; Pasick, Rena J.

    2010-01-01

    Intention, self-efficacy, perceived susceptibility, perceived benefits, and subjective norms are key constructs of health behavior theories; their predictive validity for cancer screening has not been ascertained in multiethnic populations. Participants were 1,463 African American, Chinese, Filipina, Latina, and White women aged 40 to 74 interviewed by telephone in their preferred languages. The relationship between base-line constructs and mammography 2 years later was assessed using multivariable logistic regression. Intention predicted mammography overall and among Whites (odds ratio [OR] = 5.0, 95% confidence interval [CI] = 2.4, 10), with racial/ethnic differences in association (p = .020). Self-efficacy predicted mammography overall and among Whites (OR = 3.5, 95% CI = 1.1, 11), with no racial/ethnic interaction. Perceived benefits and subjective norms were associated with screening overall and in some racial/ethnic groups. These results generally support cross-cultural applicability of four of the five constructs to screening with mixed predictive value of measures across racial/ethnic groups. Additional in-depth inquiry is required to refine assessment of constructs. PMID:19805790

  15. Sensitivity of Self-report Mammography Use in Older Women

    PubMed Central

    Craig, Benjamin M.; Quinn, Gwendolyn P.; Vadaparampil, Susan T.

    2013-01-01

    Background Recent survey evidence indicates a decline in mammography use among older women. The objective of this study was to detect sensitivity variation in self-reported mammography use and pose evidence-based suggestions to increase survey accuracy. Methods Using 1991-2006 Medicare Current Beneficiary Survey (MCBS), 15,357 women, age 65 or older, were selected based on use of mammography services. The women were interviewed in the community setting at random periods after screening and asked, “Have you had a mammogram or breast x-ray since [today's date] one year ago?” Statistical analyses were conducted between March 11 and April 28 of 2008. This study tested whether sensitivity (i.e., probability of an affirmative response) was dependent on length of the recall period and on respondent demographic and socioeconomic characteristics. Results Overall, 90.4% of the older women self-reported use; however, sensitivity decreased as the recall period lengthened (90% at 6 months, 80% at 12 months). This time effect was significantly higher among older, economically disadvantaged women. Sensitivity also decreased an additional 13.8% if the event occurred in the previous calendar year, and 3.5% if conducted in a non-English language or by proxy. Conclusion Greatest sensitivity use occurred during the 6-month period after service without straddling calendar years. These findings may aid the tailoring of future surveys for older adults, improving the recall of preventive services. PMID:19840700

  16. Preliminary results for positron emission mammography: real-time functional breast imaging in a conventional mammography gantry.

    PubMed

    Weinberg, I; Majewski, S; Weisenberger, A; Markowitz, A; Aloj, L; Majewski, L; Danforth, D; Mulshine, J; Cowan, K; Zujewski, J; Chow, C; Jones, E; Chang, V; Berg, W; Frank, J

    1996-07-01

    In order to optimally integrate radiotracer breast imaging within the breast clinic, anatomy and pathology should be easily correlated with functional nuclear medicine breast images. As a first step in the development of a hybrid functional/anatomic breast imaging platform with biopsy capability, a conventional X-ray mammography gantry was modified to image the compressed breast with positron emitters. Phantom studies with the positron emission mammography (PEM) device showed that a 1-cc hot spot could be detected within 5 min. A preliminary clinical trial demonstrated in vivo visualization of primary breast cancer within 4 min. For sites where positron-emitting radionuclides are available, PEM promises to achieve low-cost directed functional examination of breast abnormalities, with the potential for achieving X-ray correlation and image-guided biopsy.

  17. Commissioning a small-field biological irradiator using point, 2D, and 3D dosimetry techniques

    SciTech Connect

    Newton, Joseph; Oldham, Mark; Thomas, Andrew; Li Yifan; Adamovics, John; Kirsch, David G.; Das, Shiva

    2011-12-15

    Purpose: To commission a small-field biological irradiator, the XRad225Cx from Precision x-Ray, Inc., for research use. The system produces a 225 kVp x-ray beam and is equipped with collimating cones that produce both square and circular radiation fields ranging in size from 1 to 40 mm. This work incorporates point, 2D, and 3D measurements to determine output factors (OF), percent-depth-dose (PDD) and dose profiles at multiple depths. Methods: Three independent dosimetry systems were used: ion-chambers (a farmer chamber and a micro-ionisation chamber), 2D EBT2 radiochromic film, and a novel 3D dosimetry system (DLOS/PRESAGE registered ). Reference point dose rates and output factors were determined from in-air ionization chamber measurements for fields down to {approx}13 mm using the formalism of TG61. PDD, profiles, and output factors at three separate depths (0, 0.5, and 2 cm), were determined for all field sizes from EBT2 film measurements in solid water. Several film PDD curves required a scaling correction, reflecting the challenge of accurate film alignment in very small fields. PDDs, profiles, and output factors were also determined with the 3D DLOS/PRESAGE registered system which generated isotropic 0.2 mm data, in scan times of 20 min. Results: Surface output factors determined by ion-chamber were observed to gradually drop by {approx}9% when the field size was reduced from 40 to 13 mm. More dramatic drops were observed for the smallest fields as determined by EBT{approx}18% and {approx}42% for the 2.5 mm and 1 mm fields, respectively. PRESAGE registered and film output factors agreed well for fields <20 mm (where 3D data were available) with mean deviation of 2.2% (range 1%-4%). PDD values at 2 cm depth varied from {approx}72% for the 40 mm field, down to {approx}55% for the 1 mm field. EBT and PRESAGE registered PDDs agreed within {approx}3% in the typical therapy region (1-4 cm). At deeper depths the EBT curves were slightly steeper (2.5% at 5 cm

  18. Psychosocial determinants of mammography follow-up after receipt of abnormal mammography results in medically underserved women.

    PubMed

    Fair, Alecia Malin; Wujcik, Debra; Lin, Jin-Mann Sally; Zheng, Wei; Egan, Kathleen M; Grau, Ana M; Champion, Victoria L; Wallston, Kenneth A

    2010-02-01

    This article targets the relationship between psychosocial determinants and abnormal screening mammography follow-up in a medically underserved population. Health belief scales were modified to refer to diagnostic follow-up versus annual screening. A retrospective cohort study design was used. Statistical analyses were performed examining relationships among sociodemographic factors, psychosocial determinants, and abnormal mammography follow-up. Women with lower mean internal health locus of control scores (3.14) were two times more likely than women with higher mean internal health locus of control scores (3.98) to have inadequate follow-up (OR=2.53, 95% CI=1.12-5.36). Women with less than a high school education had lower cancer fatalism scores than women who had completed high school (47.5 vs. 55.2, p-value=.02) and lower mean external health locus of control scores (3.0 vs. 5.3) (p-value<.01). These constructs have implications for understanding mammography follow-up among minority and medically underserved women. Further comprehensive study of these concepts is warranted.

  19. Feasibility of lateral dose profile measurements in a small field using TLDs.

    PubMed

    Zhang, Bailin; Zhu, Jinhan; Li, Yinghui; Chen, Shaowen; Chen, Lixin; Liu, Xiaowei

    2015-02-07

    The purpose of this work was to study the feasibility of lateral dose profile measurements in a small field using thermoluminescent dosimeters (TLDs) and to evaluate the impact of the field size on the absorbed dose ratio factor fmd of LiF and Al2O3 TLDs. The Monte Carlo package BEAM/EGSNRC was used to simulate the lateral dose profile in solid water phantoms (RW3 slab phantom) with various field sizes beyond the build-up region for 6 MV x-rays, and a LiF : Mg, Cu, P (GR-200) dosimeter with dimensions of 0.1  ×  0.1  ×  0.1 cm(3) was used to measure the lateral dose profile under the same conditions as the Monte Carlo simulations. To enable comparisons between dosimeters, Gafchromic EBT3 films were used. The results indicate that (1) the measured results are in agreement with the simulated results within the uncertainty of the simulation; (2) the values of fmd for Al2O3 and LiF in a 1  ×  1 cm(2) field are 2.8% and 1.6% less, respectively, than those in a 10  ×  10 cm(2) field; and (3) within the 80% profile region, the dose differences between TLDs and solid water are less than 1%. In the 80-10% profile region, the TLD results are in agreement with the absorbed doses in the solid water within 1 mm. It is generally acceptable to ignore the impact of field size on the absorbed dose ratio factor fmd when the field sizes are larger than 1  ×  1 cm(2) for LiF and 2  ×  2 cm(2) for Al2O3. For 6 MV x-rays, the small GR-200 chip can be used to measure the relative lateral dose profiles of small fields.

  20. Evaluation of the dosimetric properties of a diode detector for small field proton radiosurgery.

    PubMed

    McAuley, Grant A; Teran, Anthony V; Slater, Jerry D; Slater, James M; Wroe, Andrew J

    2015-11-01

    The small fields and sharp gradients typically encountered in proton radiosurgery require high spatial resolution dosimetric measurements, especially below 1-2 cm diameters. Radiochromic film provides high resolution, but requires postprocessing and special handling. Promising alternatives are diode detectors with small sensitive volumes (SV) that are capable of high resolution and real-time dose acquisition. In this study we evaluated the PTW PR60020 proton dosimetry diode using radiation fields and beam energies relevant to radiosurgery applications. Energies of 127 and 157 MeV (9.7 to 15 cm range) and initial diameters of 8, 10, 12, and 20 mm were delivered using single-stage scattering and four modulations (0, 15, 30, and 60 mm) to a water tank in our treatment room. Depth dose and beam profile data were compared with PTW Markus N23343 ionization chamber, EBT2 Gafchromic film, and Monte Carlo simulations. Transverse dose profiles were measured using the diode in "edge-on" orientation or EBT2 film. Diode response was linear with respect to dose, uniform with dose rate, and showed an orientation-dependent (i.e., beam parallel to, or perpendicular to, detector axis) response of less than 1%. Diode vs. Markus depth-dose profiles, as well as Markus relative dose ratio vs. simulated dose-weighted average lineal energy plots, suggest that any LET-dependent diode response is negligible from particle entrance up to the very distal portion of the SOBP for the energies tested. Finally, while not possible with the ionization chamber due to partial volume effects, accurate diode depth-dose measurements of 8, 10, and 12 mm diameter beams were obtained compared to Monte Carlo simulations. Because of the small SV that allows measurements without partial volume effects and the capability of submillimeter resolution (in edge-on orientation) that is crucial for small fields and high-dose gradients (e.g., penumbra, distal edge), as well as negligible LET dependence over nearly the

  1. Evaluation of the dosimetric properties of a diode detector for small field proton radiosurgery.

    PubMed

    McAuley, Grant A; Teran, Anthony V; Slater, Jerry D; Slater, James M; Wroe, Andrew J

    2015-11-08

    The small fields and sharp gradients typically encountered in proton radiosurgery require high spatial resolution dosimetric measurements, especially below 1-2 cm diameters. Radiochromic film provides high resolution, but requires postprocessing and special handling. Promising alternatives are diode detectors with small sensitive volumes (SV) that are capable of high resolution and real-time dose acquisition. In this study we evaluated the PTW PR60020 proton dosimetry diode using radiation fields and beam energies relevant to radiosurgery applications. Energies of 127 and 157 MeV (9.7 to 15 cm range) and initial diameters of 8, 10, 12, and 20mm were delivered using single-stage scattering and four modulations (0, 15, 30, and 60mm) to a water tank in our treatment room. Depth dose and beam profile data were compared with PTW Markus N23343 ionization chamber, EBT2 Gafchromic film, and Monte Carlo simulations. Transverse dose profiles were measured using the diode in "edge-on" orientation or EBT2 film. Diode response was linear with respect to dose, uniform with dose rate, and showed an orientation-dependent (i.e., beam parallel to, or perpendicular to, detector axis) response of less than 1%. Diodevs. Markus depth-dose profiles, as well as Markus relative dose ratio vs. simulated dose-weighted average lineal energy plots, suggest that any LET-dependent diode response is negligible from particle entrance up to the very distal portion of the SOBP for the energies tested. Finally, while not possible with the ionization chamber due to partial volume effects, accurate diode depth-dose measurements of 8, 10, and 12 mm diameter beams were obtained compared to Monte Carlo simulations. Because of the small SV that allows measurements without partial volume effects and the capability of submillimeter resolution (in edge-on orientation) that is crucial for small fields and high-dose gradients (e.g., penumbra, distal edge), as well as negligible LET dependence over nearly the

  2. Dosimetric effects on small-field beam-modeling for stereotactic body radiation therapy

    NASA Astrophysics Data System (ADS)

    Cho, Woong; Kim, Suzy; Kim, Jung-In; Wu, Hong-Gyun; Jung, Joo-Young; Kim, Min-Joo; Suh, Tae-Suk; Kim, Jin-Young; Kim, Jong Won

    2015-02-01

    The treatment planning of stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) requires high accuracy of dosimetric data for small radiation fields. The dosimetric effects on the beam-modeling process of a treatment planning system (TPS) were investigated using different measured small-field data sets. We performed small-field dosimetry with three detectors: a CC13 ion chamber, a CC01 ion chamber, and an edge detector. Percentage depth doses (PDDs) and dose profiles for field sizes given by 3 × 3 cm2, 2 × 2 cm2, and 1 × 1 cm2 were obtained for 6 MV and 15 MV photon beams. Each measured data set was used as data input for a TPS, in which a beam-modeling process was implemented using the collapsed cone convolution (CCC) algorithm for dose calculation. The measured data were used to generate six beam-models based on each combination of detector type and photon energy, which were then used to calculate the corresponding PDDs and dose profiles for various depths and field sizes. Root mean square differences (RMSDs) between the calculated and the measured doses were evaluated for the PDDs and the dose profiles. The RMSDs of PDDs beyond the maximum dose depth were within an accuracy of 0.2-0.6%, being clinically acceptable. The RMSDs of the dose profiles corresponding to the CC13, the CC01, and the edge detector were 2.80%, 1.49%, and 1.46% for a beam energy of 6 MV and 2.34%, 1.15%, and 1.44% for a beam energy of 15 MV, respectively. The calculated results for the CC13 ion chamber showed the most discrepancy compared to the measured data, due to the relatively large sensitive volume of this detector. However, the calculated dose profiles for the detectors were not significantly different from another. The physical algorithm used in the beam-modeling process did not seem to be sensitive to blurred data measured with detectors with large sensitive volumes. Each beam-model was used to clinically evaluate lung and lymphatic node SBRT plans

  3. Glass beads and Ge-doped optical fibres as thermoluminescence dosimeters for small field photon dosimetry.

    PubMed

    Jafari, S M; Alalawi, A I; Hussein, M; Alsaleh, W; Najem, M A; Hugtenburg, R P; Bradley, D A; Spyrou, N M; Clark, C H; Nisbet, A

    2014-11-21

    An investigation has been made of glass beads and optical fibres as novel dosimeters for small-field photon radiation therapy dosimetry. Commercially available glass beads of largest dimension 1.5 mm and GeO2-doped SiO2 optical fibres of 5 mm length and 120 µm diameter were characterized as thermoluminescence dosimeters. Results were compared against Monte-Carlo simulations with BEAMnrc/DOSXYZnrc, EBT3 Gafchromic film, and a high-resolution 2D-array of liquid-filled ionization chambers. Measurements included relative output factors and dose profiles for square-field sizes of 1, 2, 3, 4, and 10 cm. A customized Solid-Water® phantom was employed, and the beads and fibres were placed at defined positions along the longitudinal axis to allow accurate beam profile measurement. Output factors and the beam profile parameters were compared against those calculated by BEAMnrc/DOSXYZnrc. The output factors and field width measurements were found to be in agreement with reference measurements to within better than 3.5% for all field sizes down to 2 cm2 for both dosimetric systems, with the beads showing a discrepancy of no more than 2.8% for all field sizes. The results confirm the potential of the beads and fibres as thermoluminescent dosimeters for use in small photon radiation field sizes.

  4. Clinical value of mammography in diagnosis and identification of breast mass

    PubMed Central

    Li, Hongjun; Zhang, Shanhua; Wang, Qingyuan; Zhu, Rongguang

    2016-01-01

    Objective: To study the effect and clinical value of mammography in the diagnosis of breast lump so as to improve the diagnosis level of breast cancer. Methods: A retrospective analysis was carried out on clinical data of 110 patients with mammary lump confirmed by pathology to study the compliance of mammography diagnosis and Pathology diagnosis in breast lump, and the detection of microcalcifications, phyllode, and observe the image performance of mammography. Taking infitrating ductal carcinoma (IDC) as an example, the correlation of image performance and clinical pathological features of different types was studied so as to predict if mammography performance was effective in the treatment and prognosis in breast cancer. Results: Taking Breast Imaging Reporting and Data System (BI-RADS) grade 4A as the critical point, the sensitivity, specificity and accuracy of mammography was 90.80% (109/120), 84.60% (126/149) and 87.40% (235/269); taking BI-RADS grade 4B as the critical point, the sensitivity, specificity and accuracy of mammography was 85.00% (102/120), 93.30% (139/149) and 89.60% (241/269); the correlation analysis suggested that, there was some kind of correlation between the mammography performance and clinical features of breast cancer. Conclusion: Mammography is worth being promoted in clinic for its significant clinical value in diagnosing and identifying breast lump. PMID:27648060

  5. Latinas’ Mammography Intention Following a Home-Based Promotores–Led Intervention

    PubMed Central

    Scheel, John R.; Molina, Yamile; Briant, Katherine J.; Ibarra, Genoveva; Lehman, Constance D.; Thompson, Beti

    2015-01-01

    Despite increases in mammography rates among Latinas, screening rates remain lower than in non-Latina Whites (NLW) and Latinas typically present with breast cancer at a later stage. Trained lay community workers (promotores) have been successfully used to increase screening mammography intention in Latinas. Little is known, however, about the potential mechanisms of these interventions, such as increased breast cancer knowledge (knowledge) and social interactions concerning mammography practices (social engagement). This prospective pre-post study examined this gap in the literature by 1) documenting changes in knowledge and social engagement after receipt of a promotores-based intervention; and 2) establishing if post-intervention knowledge and social engagement predicted mammography intention, after adjusting for socio-demographic and lifetime mammography history. There were significant increases in knowledge and social engagement about mammography. Finally, post-intervention social engagement was a significant predictor of mammography intention. Future promotores-based interventions should focus on enhancing social engagement to improve mammography intention and use. PMID:26063674

  6. 75 FR 70011 - Guidance for Industry, Mammography Quality Standards Act Inspectors, and Food and Drug...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-16

    ... HUMAN SERVICES Food and Drug Administration Guidance for Industry, Mammography Quality Standards Act Inspectors, and Food and Drug Administration Staff; The Mammography Quality Standards Act Final Regulations: Modifications and Additions to Policy Guidance Help System 13; Availability AGENCY: Food and Drug...

  7. Cultural Views, Language Ability, and Mammography Use in Chinese American Women

    ERIC Educational Resources Information Center

    Liang, Wenchi; Wang, Judy; Chen, Mei-Yuh; Feng, Shibao; Yi, Bin; Mandelblatt, Jeanne S.

    2009-01-01

    Mammography screening rates among Chinese American women have been reported to be low. This study examines whether and how culture views and language ability influence mammography adherence in this mostly immigrant population. Asymptomatic Chinese American women (n = 466) aged 50 and older, recruited from the Washington, D.C. area, completed a…

  8. Attitudes and Beliefs Associated with Mammography in a Multiethnic Population in Israel

    ERIC Educational Resources Information Center

    Baron-Epel, Orna

    2010-01-01

    This article highlights beliefs, attitudes, and barriers that are associated with mammography use in four distinct cultural and ethnic groups in Israel: veteran, ultra-orthodox, and immigrant Jewish and Arab women. A random telephone survey of 1,550 women was performed. Information from claims records concerning mammography use was obtained for…

  9. Latinas' Mammography Intention Following a Home-Based Promotores-Led Intervention.

    PubMed

    Scheel, John R; Molina, Yamile; Briant, Katherine J; Ibarra, Genoveva; Lehman, Constance D; Thompson, Beti

    2015-12-01

    Despite increases in mammography rates among Latinas, screening rates remain lower than in non-Latina Whites and Latinas typically present with breast cancer at a later stage. Trained lay community workers (promotores) have been successfully used to increase screening mammography intention in Latinas. Little is known, however, about the potential mechanisms of these interventions, such as increased breast cancer knowledge (knowledge) and social interactions concerning mammography practices (social engagement). This prospective pre-post study examined this gap in the literature by (1) documenting changes in knowledge and social engagement after receipt of a promotores-based intervention; and (2) establishing if post-intervention knowledge and social engagement predicted mammography intention, after adjusting for socio-demographic and lifetime mammography history. There were significant increases in knowledge and social engagement about mammography. Finally, post-intervention social engagement was a significant predictor of mammography intention. Future promotores-based interventions should focus on enhancing social engagement to improve mammography intention and use.

  10. Mammography use among women with and without diabetes: results from the Southern Community Cohort Study.

    PubMed

    Sanderson, Maureen; Lipworth, Loren; Han, Xijing; Beeghly-Fadiel, Alicia; Shen-Miller, David; Patel, Kushal; Blot, William J; Hargreaves, Margaret K

    2014-09-01

    Studies have shown an increased risk of breast cancer associated with diabetes which may be due to differences in mammography use among women who have diabetes compared with women who do not have diabetes. Baseline data was used from the Southern Community Cohort Study - a prospective cohort study conducted primarily among low-income persons in the southeastern United States - to examine the association between diabetes and mammography use. In-person interviews collected information on diabetes and mammography use from 14,665 white and 30,846 black women aged 40-79years between 2002 and 2009. After adjustment for potential confounding, white women with diabetes were no more likely (odds ratio [OR] 0.95, 95% confidence interval [CI] 0.85-1.06) to undergo mammography within the past 12months than white women without diabetes. Nor was there an association between diabetes and mammography use among black women (OR 1.00, 95% CI 0.93-1.07). An increase in mammography use was seen within one year following diabetes diagnosis, more so among white than black women, but this was offset by decreases thereafter. Although there was some evidence of an increase in mammography use within one year of diabetes diagnosis, these results suggest that mammography use is not related to diabetes.

  11. Does Distance Matter? Distance to Mammography Facilities and Stage at Diagnosis of Breast Cancer in Kentucky

    ERIC Educational Resources Information Center

    Huang, Bin; Dignan, Mark; Han, Daikwon; Johnson, Owen

    2009-01-01

    Background: National and regional data indicate that breast cancer early detection is low in Kentucky, especially rural regions, perhaps because access to mammography services can be problematic. Objective: This study examined the distance between residences of women diagnosed with breast cancer and the nearest mammography facility, as a risk…

  12. The Influence of Breast Self-Examination on Subsequent Mammography Participation

    PubMed Central

    Jelinski, Susan E.; Maxwell, Colleen J.; Onysko, Jay; Bancej, Christina M.

    2005-01-01

    Objectives. We evaluated whether breast self-examination (BSE) influences subsequent mammography participation. Methods. We evaluated associations between BSE and subsequent mammography participation, adjusting for baseline screening behaviors and sociodemographic, health, and lifestyle characteristics, among women aged 40 years and older using data from the longitudinal Canadian National Population Health Survey. Results. Regular performance of BSE at baseline was not associated with receipt of a recent mammogram at follow-up among all women (adjusted odds ratio [OR]=1.01; 95% confidence interval [CI]= 0.75, 1.35) or with mammography uptake among the subgroup of women reporting never use at baseline (adjusted OR=0.78; 95% CI=0.50, 1.22). Conclusions. The lack of association between performance of BSE and subsequent mammography participation suggests that not recommending BSE is unlikely to influence mammography participation. PMID:15727985

  13. Obesity, Gynecological Factors, and Abnormal Mammography Follow-Up in Minority and Medically Underserved Women

    PubMed Central

    Wujcik, Debra; Lin, Jin-Mann S.; Grau, Ana; Wilson, Veronica; Champion, Victoria; Zheng, Wei; Egan, Kathleen M.

    2009-01-01

    Abstract Background The relationship between obesity and screening mammography adherence has been examined previously, yet few studies have investigated obesity as a potential mediator of timely follow-up of abnormal (Breast Imaging Reporting and Data System [BIRADS-0]) mammography results in minority and medically underserved patients. Methods We conducted a retrospective cohort study of 35 women who did not return for follow-up >6 months from index abnormal mammography and 41 who returned for follow-up ≤6 months in Nashville, Tennessee. Patients with a BIRADS-0 mammography event in 2003–2004 were identified by chart review. Breast cancer risk factors were collected by telephone interview. Multivariate logistic regression was performed on selected factors with return for diagnostic follow-up. Results Obesity and gynecological history were significant predictors of abnormal mammography resolution. A significantly higher frequency of obese women delayed return for mammography resolution compared with nonobese women (64.7% vs. 35.3%). A greater number of hysterectomized women returned for diagnostic follow-up compared with their counterparts without a hysterectomy (77.8% vs. 22.2%). Obese patients were more likely to delay follow-up >6 months (adjusted OR 4.09, p = 0.02). Conversely, hysterectomized women were significantly more likely to return for timely mammography follow-up ≤6 months (adjusted OR 7.95, p = 0.007). Conclusions Study results suggest that weight status and gynecological history influence patients' decisions to participate in mammography follow-up studies. Strategies are necessary to reduce weight-related barriers to mammography follow-up in the healthcare system including provider training related to mammography screening of obese women. PMID:19558307

  14. Predicting cotton yield of small field plots in a cotton breeding program using UAV imagery data

    NASA Astrophysics Data System (ADS)

    Maja, Joe Mari J.; Campbell, Todd; Camargo Neto, Joao; Astillo, Philip

    2016-05-01

    One of the major criteria used for advancing experimental lines in a breeding program is yield performance. Obtaining yield performance data requires machine picking each plot with a cotton picker, modified to weigh individual plots. Harvesting thousands of small field plots requires a great deal of time and resources. The efficiency of cotton breeding could be increased significantly while the cost could be decreased with the availability of accurate methods to predict yield performance. This work is investigating the feasibility of using an image processing technique using a commercial off-the-shelf (COTS) camera mounted on a small Unmanned Aerial Vehicle (sUAV) to collect normal RGB images in predicting cotton yield on small plot. An orthonormal image was generated from multiple images and used to process multiple, segmented plots. A Gaussian blur was used to eliminate the high frequency component of the images, which corresponds to the cotton pixels, and used image subtraction technique to generate high frequency pixel images. The cotton pixels were then separated using k-means cluster with 5 classes. Based on the current work, the calculated percentage cotton area was computed using the generated high frequency image (cotton pixels) divided by the total area of the plot. Preliminary results showed (five flights, 3 altitudes) that cotton cover on multiple pre-selected 227 sq. m. plots produce an average of 8% which translate to approximately 22.3 kgs. of cotton. The yield prediction equation generated from the test site was then use on a separate validation site and produced a prediction error of less than 10%. In summary, the results indicate that a COTS camera with an appropriate image processing technique can produce results that are comparable to expensive sensors.

  15. SU-D-304-02: Magnetically Focused Proton Irradiation of Small Field Targets

    SciTech Connect

    McAuley, GA; Slater, JM; Slater, JD; Wroe, AJ

    2015-06-15

    Purpose: To investigate the use of magnetic focusing for small field proton irradiations. It is hypothesized that magnetic focusing will provide significant dose distribution benefits over standard collimated beams for fields less than 10 mm diameter. Methods: Magnets consisting of 24 segments of radiation hard samarium-cobalt adhered into hollow cylinders were designed and manufactured. Two focusing magnets were placed on a positioning track on our Gantry 1 treatment table. Proton beams with energies of 127 and 157 MeV, 15 and 30 mm modulation, and 8 mm initial diameters were delivered to a water tank using single-stage scattering. Depth dose distributions were measured using a PTW PR60020 diode detector and transverse profiles were measured with Gafchromic EBT3 film. Monte Carlo simulations were also performed - both for comparison with experimental data and to further explore the potential of magnetic focusing in silica. For example, beam spot areas (based on the 90% dose contour) were matched at Bragg depth between simulated 100 MeV collimated beams and simulated beams focused by two 400 T/m gradient magnets. Results: Preliminary experimental results show 23% higher peak to entrance dose ratios and flatter spread out Bragg peak plateaus for 8 mm focused beams compared with uncollimated beams. Monte Carlo simulations showed 21% larger peak to entrance ratios and a ∼9 fold more efficient dose to target delivery compared to spot-sized matched collimated beams. Our latest results will be presented. Conclusion: Our results suggest that rare earth focusing magnet assemblies could reduce skin dose and beam number while delivering dose to nominally spherical radiosurgery targets over a much shorter time compared to unfocused beams. Immediate clinical applications include those associated with proton radiosurgery and functional radiosurgery of the brain and spine, however expanded treatment sites can be also envisaged.

  16. SU-E-T-376: Evaluation of a New Stereotactic Diode for Small Field Dosimetry

    SciTech Connect

    Kralik, J; Kosterin, P; Mooij, R; Solberg, T

    2015-06-15

    Purpose: To evaluate the performance of a new stereotactic diode for dosimetry of small photon fields. Methods: A new stereotactic diode, consisting of an unshielded p-type silicon chip, and with improved radiation hardness energy dependence was recently developed (IBA Dosimetry, Schwarzenbruch, Germany). The diode has an active volume of 0.6 mm dia. x 0.02 mm thick. Two new diodes were evaluated, one which was pre-irradiated to 100kGy with 10 MeV electrons and another which received no prior irradiation. Sensitivity, stability, reproducibility, and linearity as a function of dose were assessed. Beam profiles and small field output factors were measured on a CyberKnife (CK) and compared with measurements using two commercially available diodes. Results: The new diodes exhibit linear behavior (within 0.6%) over a dose range 0.02 – 50 Gy; a commercially available device exhibits excursions of up to 4% over the same range. The sensitivity is 4.1 and 3.8 nC/Gy for the un-irradiated and pre-irradiated diodes, respectively. When irradiated with 150 Gy in dose increments of 5, 20 and 35 Gy, both new diodes provide a stable response within 0.5%. Output factors measured with the two new diodes are identical and compare favorably with other commercially available diodes and published data. Similarly, no differences in measured field size or penumbra were observed among the devices tested. Conclusion: The new diodes show excellent stability and sensitivity. The beam characterization in terms of output factors and beam profiles is consistent with that obtained with commercially available diodes.

  17. SU-E-I-88: Mammography Imaging: Does Positioning Matter?

    SciTech Connect

    Zhang, J; Szabunio, M

    2014-06-01

    Purpose: In mammography, compression is imperative for quality images and glandular radiation exposure dose. The thickness of the compressed breast directly determines mammography acquisition parameters. The compressed thickness varies due to variation in technologist practice, even for the same patient imaged at different time. This study is to investigate potential effect of the variation in breast positioning on radiation dose and image quality. Methods: Radiation dose at different thicknesses was measured with a BR-12 breast phantom for both conventional craniocaudal view and tomosynthesis in a Hologic Tomosynthesis mammography system. The CIRS stereotactic needle biopsy training phantom embedded dense masses and microcalcification in various sizes were imaged for image quality evaluation. Radiologists evaluated images. Clinical mammograms from the same patient but acquired at different time were retrospectively retrieved to evaluate potential effects of variation in positioning. Results: Acquisition parameters (kVp and mAs) increase with the increased phantom thickness. Radiation exposure increases following an exponential trend. The stereotactic phantom images showed loss of spatial and contrast resolution with inappropriate positioning. The compressed pressure may not be a good indicator for appropriate positioning. The inclusion of different amount of pectoralis muscle may lead to the same compressed pressure but different compressed thickness. The initial retrospective study of 3 patients showed that there were potential large variations in positioning the same patient at different examination time, resulting in large variations in patient radiation dose and image quality. Conclusion: Variations in patient positioning potentially influence patient radiation dose and image quality. The technologist has the critical responsibility to position patient to provide quality images in spite of different breast and body types. To reduce intra and inter practice

  18. Knowledge Discovery from Structured Mammography Reports Using Inductive Logic Programming

    PubMed Central

    Burnside, Elizabeth S.; Davis, Jesse; Costa, Vítor Santos; de Castro Dutra, Inês; Kahn, Charles E.; Fine, Jason; Page, David

    2005-01-01

    The development of large mammography databases provides an opportunity for knowledge discovery and data mining techniques to recognize patterns not previously appreciated. Using a database from a breast imaging practice containing patient risk factors, imaging findings, and biopsy results, we tested whether inductive logic programming (ILP) could discover interesting hypotheses that could subsequently be tested and validated. The ILP algorithm discovered two hypotheses from the data that were 1) judged as interesting by a subspecialty-trained mammographer and 2) validated by analysis of the data itself. PMID:16779009

  19. Volumetric lean percentage measurement using dual energy mammography

    PubMed Central

    Ducote, Justin L.; Klopfer, Michael J.; Molloi, S.

    2011-01-01

    Purpose: Currently, there is no accepted standard for measuring breast density. Dual energy mammography, which has demonstrated accurate measurement in phantoms, has been proposed as one possible method. To examine the use of chemical analysis as a possible means to validate breast density measurements from dual energy mammography, a bovine tissue model was investigated. Known quantities of lean and adipose tissue were compared with composition values measured from dual energy images and chemical analysis. Methods: Theoretical simulations were performed to assess the impact variations in breast composition would have on measurement of breast density from a single calibration. Fourteen ex-vivo tissue samples composed of varying amounts of pure lean tissue and pure adipose tissue (lean percentage) from 0 to 100%, in increments of 10%, were imaged using dual energy mammography. This was followed by chemical analysis based on desiccation, trituration, and fat extraction with petroleum ether to determine water, lipid, and protein content. The volumetric lean percentage (VLP) as measured from images (VLPI) and as derived from chemical analysis data (VLPCA) were compared with the VLP calculated from measurements of sample mass with a scale (VLPM). Finally, data from the bovine tissue model in this study were compared to compositional data from a previous report of human tissue composition. Results: The results from simulation suggest a substantial impact on measuring breast density is likely due to changes in anatomical breast composition. VLPI was related to the VLPM by VLPI = 1.53 VLPM + 10.0 (r2>0.99). VLPCA was related to VLPM by VLPCA = 0.76 VLPM + 22.8 (r2>0.99). VLPI was related to VLPCA by VLPI = 2.00 VLPCA − 35.6 (r2>0.99). Bovine adipose tissue was shown to be very similar to human adipose tissue in terms of water, lipid, and protein content with RMS differences of 1.2%. Bovine lean tissue was shown to be very similar to human skeletal

  20. Toward Effective and Compelling Instruction for High School eCommerce Students: Results from a Small Field Study

    ERIC Educational Resources Information Center

    Luterbach, Kenneth J.; Rodriguez, Diane; Love, Lakecia

    2012-01-01

    This paper describes an instructional development effort to create effective and compelling instruction for eCommerce students. Results from a small field study inform the development project. Four high school students in an eCommerce course completed the standalone tutorial developed to teach them how to create a web page in the HyperText Markup…

  1. Image quality, threshold contrast and mean glandular dose in CR mammography.

    PubMed

    Jakubiak, R R; Gamba, H R; Neves, E B; Peixoto, J E

    2013-09-21

    In many countries, computed radiography (CR) systems represent the majority of equipment used in digital mammography. This study presents a method for optimizing image quality and dose in CR mammography of patients with breast thicknesses between 45 and 75 mm. Initially, clinical images of 67 patients (group 1) were analyzed by three experienced radiologists, reporting about anatomical structures, noise and contrast in low and high pixel value areas, and image sharpness and contrast. Exposure parameters (kV, mAs and target/filter combination) used in the examinations of these patients were reproduced to determine the contrast-to-noise ratio (CNR) and mean glandular dose (MGD). The parameters were also used to radiograph a CDMAM (version 3.4) phantom (Artinis Medical Systems, The Netherlands) for image threshold contrast evaluation. After that, different breast thicknesses were simulated with polymethylmethacrylate layers and various sets of exposure parameters were used in order to determine optimal radiographic parameters. For each simulated breast thickness, optimal beam quality was defined as giving a target CNR to reach the threshold contrast of CDMAM images for acceptable MGD. These results were used for adjustments in the automatic exposure control (AEC) by the maintenance team. Using optimized exposure parameters, clinical images of 63 patients (group 2) were evaluated as described above. Threshold contrast, CNR and MGD for such exposure parameters were also determined. Results showed that the proposed optimization method was effective for all breast thicknesses studied in phantoms. The best result was found for breasts of 75 mm. While in group 1 there was no detection of the 0.1 mm critical diameter detail with threshold contrast below 23%, after the optimization, detection occurred in 47.6% of the images. There was also an average MGD reduction of 7.5%. The clinical image quality criteria were attended in 91.7% for all breast thicknesses evaluated in

  2. Image quality, threshold contrast and mean glandular dose in CR mammography

    NASA Astrophysics Data System (ADS)

    Jakubiak, R. R.; Gamba, H. R.; Neves, E. B.; Peixoto, J. E.

    2013-09-01

    In many countries, computed radiography (CR) systems represent the majority of equipment used in digital mammography. This study presents a method for optimizing image quality and dose in CR mammography of patients with breast thicknesses between 45 and 75 mm. Initially, clinical images of 67 patients (group 1) were analyzed by three experienced radiologists, reporting about anatomical structures, noise and contrast in low and high pixel value areas, and image sharpness and contrast. Exposure parameters (kV, mAs and target/filter combination) used in the examinations of these patients were reproduced to determine the contrast-to-noise ratio (CNR) and mean glandular dose (MGD). The parameters were also used to radiograph a CDMAM (version 3.4) phantom (Artinis Medical Systems, The Netherlands) for image threshold contrast evaluation. After that, different breast thicknesses were simulated with polymethylmethacrylate layers and various sets of exposure parameters were used in order to determine optimal radiographic parameters. For each simulated breast thickness, optimal beam quality was defined as giving a target CNR to reach the threshold contrast of CDMAM images for acceptable MGD. These results were used for adjustments in the automatic exposure control (AEC) by the maintenance team. Using optimized exposure parameters, clinical images of 63 patients (group 2) were evaluated as described above. Threshold contrast, CNR and MGD for such exposure parameters were also determined. Results showed that the proposed optimization method was effective for all breast thicknesses studied in phantoms. The best result was found for breasts of 75 mm. While in group 1 there was no detection of the 0.1 mm critical diameter detail with threshold contrast below 23%, after the optimization, detection occurred in 47.6% of the images. There was also an average MGD reduction of 7.5%. The clinical image quality criteria were attended in 91.7% for all breast thicknesses evaluated in both

  3. Digital Breast Tomosynthesis guided Near Infrared Spectroscopy: Volumetric estimates of fibroglandular fraction and breast density from tomosynthesis reconstructions.

    PubMed

    Vedantham, Srinivasan; Shi, Linxi; Michaelsen, Kelly E; Krishnaswamy, Venkataramanan; Pogue, Brian W; Poplack, Steven P; Karellas, Andrew; Paulsen, Keith D

    A multimodality system combining a clinical prototype digital breast tomosynthesis with its imaging geometry modified to facilitate near-infrared spectroscopic imaging has been developed. The accuracy of parameters recovered from near-infrared spectroscopy is dependent on fibroglandular tissue content. Hence, in this study, volumetric estimates of fibroglandular tissue from tomosynthesis reconstructions were determined. A kernel-based fuzzy c-means algorithm was implemented to segment tomosynthesis reconstructed slices in order to estimate fibroglandular content and to provide anatomic priors for near-infrared spectroscopy. This algorithm was used to determine volumetric breast density (VBD), defined as the ratio of fibroglandular tissue volume to the total breast volume, expressed as percentage, from 62 tomosynthesis reconstructions of 34 study participants. For a subset of study participants who subsequently underwent mammography, VBD from mammography matched for subject, breast laterality and mammographic view was quantified using commercial software and statistically analyzed to determine if it differed from tomosynthesis. Summary statistics of the VBD from all study participants were compared with prior independent studies. The fibroglandular volume from tomosynthesis and mammography were not statistically different (p=0.211, paired t-test). After accounting for the compressed breast thickness, which were different between tomosynthesis and mammography, the VBD from tomosynthesis was correlated with (r =0.809, p<0.001), did not statistically differ from (p>0.99, paired t-test), and was linearly related to, the VBD from mammography. Summary statistics of the VBD from tomosynthesis were not statistically different from prior studies using high-resolution dedicated breast computed tomography. The observation of correlation and linear association in VBD between mammography and tomosynthesis suggests that breast density associated risk measures determined for

  4. Determination of small-field correction factors for cylindrical ionization chambers using a semiempirical method

    NASA Astrophysics Data System (ADS)

    Park, Kwangwoo; Bak, Jino; Park, Sungho; Choi, Wonhoon; Park, Suk Won

    2016-02-01

    A semiempirical method based on the averaging effect of the sensitive volumes of different air-filled ionization chambers (ICs) was employed to approximate the correction factors for beam quality produced from the difference in the sizes of the reference field and small fields. We measured the output factors using several cylindrical ICs and calculated the correction factors using a mathematical method similar to deconvolution; in the method, we modeled the variable and inhomogeneous energy fluence function within the chamber cavity. The parameters of the modeled function and the correction factors were determined by solving a developed system of equations as well as on the basis of the measurement data and the geometry of the chambers. Further, Monte Carlo (MC) computations were performed using the Monaco® treatment planning system to validate the proposed method. The determined correction factors (k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} ) were comparable to the values derived from the MC computations performed using Monaco®. For example, for a 6 MV photon beam and a field size of 1  ×  1 cm2, k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} was calculated to be 1.125 for a PTW 31010 chamber and 1.022 for a PTW 31016 chamber. On the other hand, the k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} values determined from the MC computations were 1.121 and 1.031, respectively; the difference between the proposed method and the MC computation is less than 2%. In addition, we determined the k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} values for PTW 30013, PTW 31010, PTW 31016, IBA FC23-C, and IBA CC13 chambers as well. We devised a method for determining k{{Q\\text{msr}},Q}{{f\\text{smf}}, {{f}\\text{ref}}} from both the measurement of the output factors and model-based mathematical computation. The proposed method can be useful in case the MC simulation would not be applicable for the clinical settings.

  5. SU-E-T-506: Intercomparison Study On Small Field Output Factor Measurements

    SciTech Connect

    Talamonti, C; Casati, M; Compagnucci, A; Arilli, C; Greto, D; Marrazzo, L; Pallotta, S; Zani, M; Marinelli, M; Verona, G; Menichelli, D; Scotti, L

    2015-06-15

    Purpose In radiotherapy, uncertainties due to small field measurements (SFM) introduce systematic errors to the treatment process and the development of new dosimeters for quality assurance programs is a challenge. In this work we analyze the behavior of seven detectors measuring output factors of 6MV photon beam. Methods The dosimeters employed are: a single cristal diamond detector (SCCD) developed at the University of Rome Tor Vergata, a silicon diode developed within the project MAESTRO, a IBA Razor silicon diode, A1SL and A26 Exradin ion chambers, an EBT3 Gafchromic film and the Exradin W1 Scintillator.Diamond sensitive volume is a cylinder 2.2mm in diameter and 1μm thick. MAESTRO diode is 2×2mm2 active area. Razor sensitive volume is a cylinder 0.6 mm in diameter and 0.02 mm thick. A16 and A1Sl have a collecting volume of 0,015cc and 0,053cc. The W1 is an optical fiber with an active volume of 0.002cc. All measurements were performed in a water phantom, with detector positioned at the isocenter (SSD=90cm, d=10cm), MAESTRO diode being sandwiched in solid water to obtain an equivalent experimental setup. Results These measurements are challenging due to the absence of charged particle equilibrium conditions, detector size and positioning problems. They are in good agreement among each other, especially GAF, Razor, W1 and SCDD. Maximum deviations reported are related to the field 0.8×0.8cm2 for MAESTRO and chambers data with respect to EBT3: around 15% (A1SLvsEBT3), 16% (MAESTROvsEBT3). Razor and W1 show a deviation around 3% with respect to SCDD. Conclusion In this work measurements made with a variety of detectors are compared. These study show the possibility to choose different detectors for SFM and that smaller ion chambers are still not competitive with solid state detectors. Silicon, diamond and optical fiber dosimeters show a similar behavior with minor discrepancies for the smallest field.

  6. SU-E-T-246: Detector Selection for Small Field Measurements, a Comparative Study

    SciTech Connect

    Sigler, M; Pavord, D; Irwin, J; Kriminski, S

    2015-06-15

    Purpose: To compare commercially available detectors for small field dosimetry. Methods: PTW (Freiburg, Germany) diode E, PTW microDiamond, and SunNuclear (Melbourne, FL) Edge detector were used to measure output factors, PDD, and profiles on a Varian iX linear accelerator (Varian Medical Systems, Palo Alto, CA) using 6MV and 18MV photon beams. The water tank was set to 100cm SSD. Centering profiles at 5cm and 20cm depth confirmed an offset <0.1mm. High resolution PDD (0.1mm) aligned the collecting volume at water surface. For setup and linearity verification, PDD and profiles were matched to annual measurements, which were performed with an A1SL ion chamber.Scans were taken for 6X and 18X, for 10cmx10cm, 10cmx2cm, 10cmx1cm, and 10cmx0.5cm fields. Profiles were measured at Dmax (6X=1.5cm, 18X=3.5cm), 5cm, 10cm, and 20cm depths. All fields used 10cmx10cm jaws with the MLC defining the field in the X-direction. PDDs used 2mm step size and 0.2s discrete collecting time. Profiles used 1mm step size and a 0.4s discrete collecting time. Results: The PTW diode E and Edge detector exhibit centering stability, but all detectors require vertical shifts from Vendor defined vertical alignment. Output factor measurements reveal good agreement between detectors. The Edge detector demonstrates the sharpest penumbra and the closest consistent match to ion chamber measurements in the out of field regions for 6MV (3.2%). Each detector provides comparable curve quality for PDDs, with a maximum difference across detectors giving a standard deviation of 0.6% at 30cm depth, 18X, and 10cmx0.5cm. Profiles match closely across all detectors, depths, energies, and field sizes. The microDiamond detector produces the largest penumbra width, largest deviation from ion chamber dose in the tail region for 6MV, and exhibits centering instability. Conclusion: Based on our findings, the Edge detector was chosen for stereotactic measurements. The PTW diode E is an acceptable alternative.

  7. Digital X-Ray Imaging

    NASA Astrophysics Data System (ADS)

    Dance, David R.

    The use of X-ray image receptors that produce a digital image is becoming increasingly important. Possible benefits include improved dynamic range and detective quantum efficiency, improved detectability for objects of low intrinsic contrast, and reduced radiation dose. The image can be available quickly. The display is separated from the image capture so that processing and contrast adjustment are possible before the image is viewed. The availability of a digital image means ready input into PACS and opens up the possibility of computer-aided detection and classification of abnormality. Possible drawbacks of digital systems include high cost, limited high contrast resolution and the fact that their clinical value is sometimes not proven in comparison with conventional, analogue techniques. The high contrast resolution attainable with such systems is discussed and the problem of sampling limitations and aliasing considered. The properties and limitations of digital systems using computed radiography, caesium iodide plus CCDs and active matrix arrays with either caesium iodide or selenium detectors are demonstrated. Examples are given of digital systems for mammography and general radiography and their performance is demonstrated in terms of clinical assessment and measurements of the modulation transfer function and detective quantum efficiency.

  8. Comparison of 2D versus 3D mammography with screening cases: an observer study

    NASA Astrophysics Data System (ADS)

    Fernandez, James Reza; Deshpande, Ruchi; Hovanessian-Larsen, Linda; Liu, Brent

    2012-02-01

    Breast cancer is the most common type of non-skin cancer in women. 2D mammography is a screening tool to aid in the early detection of breast cancer, but has diagnostic limitations of overlapping tissues, especially in dense breasts. 3D mammography has the potential to improve detection outcomes by increasing specificity, and a new 3D screening tool with a 3D display for mammography aims to improve performance and efficiency as compared to 2D mammography. An observer study using human studies collected from was performed to compare traditional 2D mammography with this new 3D mammography technique. A prior study using a mammography phantom revealed no difference in calcification detection, but improved mass detection in 2D as compared to 3D. There was a significant decrease in reading time for masses, calcifications, and normals in 3D compared to 2D, however, as well as more favorable confidence levels in reading normal cases. Data for this current study is currently being obtained, and a full report should be available in the next few weeks.

  9. Dosimetry in Mammography: Average Glandular Dose Based on Homogeneous Phantom

    NASA Astrophysics Data System (ADS)

    Benevides, Luis A.; Hintenlang, David E.

    2011-05-01

    The objective of this study was to demonstrate that a clinical dosimetry protocol that utilizes a dosimetric breast phantom series based on population anthropometric measurements can reliably predict the average glandular dose (AGD) imparted to the patient during a routine screening mammogram. AGD was calculated using entrance skin exposure and dose conversion factors based on fibroglandular content, compressed breast thickness, mammography unit parameters and modifying parameters for homogeneous phantom (phantom factor), compressed breast lateral dimensions (volume factor) and anatomical features (anatomical factor). The patient fibroglandular content was evaluated using a calibrated modified breast tissue equivalent homogeneous phantom series (BRTES-MOD) designed from anthropomorphic measurements of a screening mammography population and whose elemental composition was referenced to International Commission on Radiation Units and Measurements Report 44 and 46 tissues. The patient fibroglandular content, compressed breast thickness along with unit parameters and spectrum half-value layer were used to derive the currently used dose conversion factor (DgN). The study showed that the use of a homogeneous phantom, patient compressed breast lateral dimensions and patient anatomical features can affect AGD by as much as 12%, 3% and 1%, respectively. The protocol was found to be superior to existing methodologies. The clinical dosimetry protocol developed in this study can reliably predict the AGD imparted to an individual patient during a routine screening mammogram.

  10. Dosimetry in Mammography: Average Glandular Dose Based on Homogeneous Phantom

    SciTech Connect

    Benevides, Luis A.; Hintenlang, David E.

    2011-05-05

    The objective of this study was to demonstrate that a clinical dosimetry protocol that utilizes a dosimetric breast phantom series based on population anthropometric measurements can reliably predict the average glandular dose (AGD) imparted to the patient during a routine screening mammogram. AGD was calculated using entrance skin exposure and dose conversion factors based on fibroglandular content, compressed breast thickness, mammography unit parameters and modifying parameters for homogeneous phantom (phantom factor), compressed breast lateral dimensions (volume factor) and anatomical features (anatomical factor). The patient fibroglandular content was evaluated using a calibrated modified breast tissue equivalent homogeneous phantom series (BRTES-MOD) designed from anthropomorphic measurements of a screening mammography population and whose elemental composition was referenced to International Commission on Radiation Units and Measurements Report 44 and 46 tissues. The patient fibroglandular content, compressed breast thickness along with unit parameters and spectrum half-value layer were used to derive the currently used dose conversion factor (DgN). The study showed that the use of a homogeneous phantom, patient compressed breast lateral dimensions and patient anatomical features can affect AGD by as much as 12%, 3% and 1%, respectively. The protocol was found to be superior to existing methodologies. The clinical dosimetry protocol developed in this study can reliably predict the AGD imparted to an individual patient during a routine screening mammogram.

  11. Frequency-domain optical mammography: edge effect corrections.

    PubMed

    Fantini, S; Franceschini, M A; Gaida, G; Gratton, E; Jess, H; Mantulin, W W; Moesta, K T; Schlag, P M; Kaschke, M

    1996-01-01

    We have investigated the problem of edge effects in laser-beam transillumination scanning of the human breast. Edge effects arise from tissue thickness variability along the scanned area, and from lateral photon losses through the sides of the breast. Edge effects can be effectively corrected in frequency-domain measurements by employing a two-step procedure: (1) use of the phase information to calculate an effective tissue thickness for each pixel location; (2) application of the knowledge of tissue thickness to calculate an edge-corrected optical image from the ac signal image. The measurements were conducted with a light mammography apparatus (LIMA) designed for feasibility tests in the clinical environment. Operating in the frequency-domain (110 MHz), this instrument performs a transillumination optical scan at two wavelengths (685 and 825 nm). We applied the proposed two-step procedure to data from breast phantoms and from human breasts. The processed images provide higher contrast and detectability in optical mammography with respect to raw data breast images.

  12. Breast screening with mammography: Overview of Swedish randomized trials

    SciTech Connect

    Nystroem, L.; Wall, S. . Dept. of Epidemiology and Public Health); Rutqvist, L.E. . Oncologic Centre); Lindgren, A. ); Lindqvist, M. ); Ryden, S. ); Andersson, J. ); Bjurstam, N. ); Fagerberg, G. ); Frisell, J. ); Tabar, L. ); Larson, L.G. . Oncologic Centre)

    1993-04-17

    Despite encouraging results from screening trials the efficacy of mammography in reducing mortality remains somewhat controversial. Five studies have been done in Sweden. This overview, reveals a 24% significant reduction of breast cancer mortality among those invited to mammography screening compared with those not invited. To avoid the potential risk of differential misclassification causes of death were assessed by an independent end-point committee after a blinded review of all fatal breast cancer cases. The mortality reduction was similar, irrespective of the end-point used for evaluation (breast cancer as underlying cause of death or breast cancer present at death). There was a consistent risk reduction associated with screening in all studies, although the point estimate of the relative risk for all ages varied non-significantly between 0.68 and 0.84. The cumulative breast cancer mortality by time since randomization was estimated at 1.3 per 1,000 within 6 years in the invited group compared with 1.6 in the control group. The corresponding figures after 9 years are 2.6 and 3.3 and after 12 years 3.9 and 5.1.

  13. Diagnostic criteria for mass lesions differentiating in electrical impedance mammography

    NASA Astrophysics Data System (ADS)

    A, Karpov; M, Korotkova

    2013-04-01

    The purpose of this research was to determine the diagnostic criteria for differentiating volumetric lesions in the mammary gland in electrical impedance mammography. The research was carried out utilizing the electrical impedance computer mammograph llMEIK v.5.6gg®, which enables to acquire images of 3-D conductivity distribution layers within mamma's tissues up to 5 cm depth. The weighted reciprocal projection method was employed to reconstruct the 3-D electric conductivity distribution of the examined organ. The results of 3,710 electrical impedance examinations were analyzed. The analysis of a volumetric lesion included assessment of its shape, contour, internal electrical structure and changes of the surrounding tissues. Moreover, mammary gland status was evaluated with the help of comparative and age-related electrical conductivity curves. The diagnostic chart is provided. Each criterion is measured in points. Using the numerical score for evaluation of mass and non-volumetric lesions within the mammary gland in electrical impedance mammography allowed comparing this information to BI-RADS categories developed by American College of Radiology experts. The article is illustrated with electrical impedance mammograms and tables.

  14. Using physician correspondence and postcard reminders to promote mammography use.

    PubMed Central

    Taplin, S H; Anderman, C; Grothaus, L; Curry, S; Montano, D

    1994-01-01

    OBJECTIVES. In a health maintenance organization that mails letters to women recommending that they schedule mammograms, we conducted a randomized trial to evaluate simple methods of increasing the use of screening mammography. METHODS. Using a 2 x 2 factorial design, we tested the effects of (1) mailing the recommendation letter from each woman's primary care physician rather than from the program director and (2) sending a subsequent reminder postcard. RESULTS. Sending a reminder postcard nearly doubled the odds that women would get mammograms within 1 year (participate). The letter from the woman's personal physician had no effect. Attending a clinic more than 45 minutes from the screening center, being a current smoker, or being in fair or poor health were negatively associated with subsequently obtaining a mammogram. The odds of participation doubled if women had had previous mammograms. CONCLUSIONS. When preceded by written recommendations to schedule mammograms, reminder postcards effectively increased participation. Future randomized trials to promote use of screening mammography should compare interventions with a reminder condition. PMID:8154558

  15. Multistrategy health education program to increase mammography use among women ages 65 and older.

    PubMed Central

    Rimer, B K; Resch, N; King, E; Ross, E; Lerman, C; Boyce, A; Kessler, H; Engstrom, P F

    1992-01-01

    Mammography use decreases with age although the risk of breast cancer increases with age. Medicare now provides biennial coverage for screening mammography. This study was designed to simulate the Medicare condition by subsidizing mammography among women in eight retirement communities in the metropolitan Philadelphia area. The study also measured the impact of health education interventions and the presence of a mobile mammography van on increased use of mammography. Retirement communities were assigned randomly to the control (cost subsidy alone) or experimental group (cost subsidy, mammography van, and tailored health education interventions). A total of 412 women ages 65 and older who had not had mammograms in the previous year were surveyed at baseline and 3 months later. Analytic techniques reflected the cluster nature of the randomization. Women in the experimental group were significantly more likely than the control group women to have obtained mammograms. Forty-five percent of the experimental group women compared with 12 percent of the control group women subsequently had mammograms in the 3 months after the baseline interview (P less than .001). Logistic regression analysis for mammography use indicated an odds ratio of 6.1 associated with being in the experimental group. For women in the experimental group, a separate logistic regression for mammography use showed an odds ratio of 7.8 associated with attendance at the educational presentation. The results suggest that Medicare coverage alone will not increase mammography use sufficiently to achieve year 2000 objectives. However, the addition of access enhancing and health education interventions boosts utilization dramatically. PMID:1641432

  16. SU-E-T-431: Vertically-Oriented Farmer-Type Chamber for Small-Field Applications

    SciTech Connect

    Ahmad, M; Chu, A; Lincoln, H; Chen, Z; Deng, J; Nath, R

    2014-06-01

    Purpose: To introduce a non-conventional measurement setup using Farmer-type chambers to accommodate several situations of small-field dose measurements without compromising accuracy. The validation of this technique was demonstrated for photon small-field output measurements, and electron small-field percentage depth-dose (PDD) measurements. Methods: Initial chamber alignment was performed using the conventional (horizontally-oriented) chamber setup. A PDD was acquired for a 4×4 cm{sup 2} field size using this arrangement. This PDD was used as a positional reference for the vertically-oriented chamber (VOC) configuration. Next, a PDD was acquired for a 4×4 cm{sup 2} field size with the VOC. The PDD's were superimposed to find the effective shift of the VOC. Using the shifted VOC setup, photon small-field output factors were measured and compared to stereotactic diode output factor measurements. Additionally, electron smallfield PDD's were acquired using the VOC setup and results were compared to electron Monte Carlo (eMC) predictions in the Eclipse treatment planning system (TPS). Results: (1) For photon small-field output factors field-sizes 2×2 cm{sup 2} and larger, the difference between the VOC setup and SFD measurements were less than 0.8%. For field sizes less than 2×2 cm{sup 2} discrepancies ranged from 4.0 to 10.6%. (2) PDD's measured by VOC setup show better than 1.6% agreement as compared to eMC for all electron energies measured down to the 80% depth on the 2×2 cm{sup 2} PDD curve. Disagreement between the VOC setup measurement and eMC calculations for depths down to the 50% depth on the PDD curve is 3.6% or less. Conclusion: Using the VOC setup, it is possible to use a conventional farmer chamber for small field-size measurements down to 2×2 cm{sup 2} field size without sacrificing the accuracy of measurements.

  17. Digital Breast Tomosynthesis: State of the Art

    PubMed Central

    Vedantham, Srinivasan; Vijayaraghavan, Gopal R.; Kopans, Daniel B.

    2015-01-01

    This topical review on digital breast tomosynthesis (DBT) is provided with the intent of describing the state of the art in terms of technology, results from recent clinical studies, advanced applications, and ongoing efforts to develop multimodality imaging systems that include DBT. Particular emphasis is placed on clinical studies. The observations of increase in cancer detection rates, particularly for invasive cancers, and the reduction in false-positive rates with DBT in prospective trials indicate its benefit for breast cancer screening. Retrospective multireader multicase studies show either noninferiority or superiority of DBT compared with mammography. Methods to curtail radiation dose are of importance. © RSNA, 2015 PMID:26599926

  18. TU-CD-207-04: Radiation Exposure Comparisons of CESM with 2D FFDM and 3D Tomosynthesis Mammography

    SciTech Connect

    James, J; Boltz, T; Pavlicek, W

    2015-06-15

    Purpose: While mammography is considered the standard for front-line breast cancer screening, image sensitivity and specificity can be affected by factors like dense breast tissue. Contrast-enhanced spectral mammography (CESM) shows promising initial results for dense breasts but comes at the cost of increased dose compared with full-field-digital-mammography (FFDM). The goal of this study is to quantitatively assess the dose increase of CESM in comparison with 2D-FFDM and 3D-Tomo at varying breast thickness. Methods: The experiments were conducted on a Hologic-Selenia-Dimensions system that performed 2D-FFDM, 3D-Tomo and CESM (high and low energies) on regular (50/50) and dense (70/30) breast tissue-mimicking phantoms. Both the phantoms had 6, 1-cm thick slabs (total thickness 6cm), compressed at 20-lbs using an 18×24 paddle. A single exposure was performed for each of the 3 mammo techniques with the following settings: AEC-Auto; Focal Spot-Large; kVp-Auto; mAs- Auto, Target/Filter combination-Auto; AEC Sensor/Exposure compensation Step-2/0. Average glandular dose (AGD) in mGy was obtained and compared as a function of breast thickness (1 – 6 cm) for both the phantom types. Results: The study shows that dose from the total CESM from 50/50 phantom at a breast thickness of a) 4.5 cm was 37.5% higher than 2D-FFDM and 30% higher than 3D-Tomo, b) 6 cm was 36.2% higher than 2D-FFDM and 41% higher than 3D-Tomo. For a dense breast tissue of 70/30 phantom, it was found that CESM dose at a breast thickness of: a) 4.5 cm was 33.3% higher than 2D-FFDM and 28.8% higher than 3D-Tomo, b) 6 cm was 35.4% higher than 2D-FFDM and 48.0% higher than 3D-Tomo. The overall CESM dose for the dense breast phantom was 12.5% higher at 4.5cm and 35% higher at 6 cm compared to the 50/50 phantom. Conclusion: This quantitative comparison study showed that CESM technique has an increased radiation dose compared to conventional 2D-FFDM and 3D-Tomo.

  19. Dynamical Tuning of the Initial Condition in Small Field Inflations - Can We Testify the CW Mechanism in the Universe

    NASA Astrophysics Data System (ADS)

    Iso, Satoshi

    I explain the cosmological consequence of the particle physics models with the Coleman-Weinberg (CW) type potential. Such particle physics models generally predict the small field inflation (SFI), but the SFI requires a very unnatural fine-tuning of the initial condi- tion. In this talk, I reviewed our proposal1 to solve the fine-tuning problem dynamically by a trapping of the inflaton field due to the preheating before the SFI starts.

  20. Multi-scale textural feature extraction and particle swarm optimization based model selection for false positive reduction in mammography.

    PubMed

    Zyout, Imad; Czajkowska, Joanna; Grzegorzek, Marcin

    2015-12-01

    The high number of false positives and the resulting number of avoidable breast biopsies are the major problems faced by current mammography Computer Aided Detection (CAD) systems. False positive reduction is not only a requirement for mass but also for calcification CAD systems which are currently deployed for clinical use. This paper tackles two problems related to reducing the number of false positives in the detection of all lesions and masses, respectively. Firstly, textural patterns of breast tissue have been analyzed using several multi-scale textural descriptors based on wavelet and gray level co-occurrence matrix. The second problem addressed in this paper is the parameter selection and performance optimization. For this, we adopt a model selection procedure based on Particle Swarm Optimization (PSO) for selecting the most discriminative textural features and for strengthening the generalization capacity of the supervised learning stage based on a Support Vector Machine (SVM) classifier. For evaluating the proposed methods, two sets of suspicious mammogram regions have been used. The first one, obtained from Digital Database for Screening Mammography (DDSM), contains 1494 regions (1000 normal and 494 abnormal samples). The second set of suspicious regions was obtained from database of Mammographic Image Analysis Society (mini-MIAS) and contains 315 (207 normal and 108 abnormal) samples. Results from both datasets demonstrate the efficiency of using PSO based model selection for optimizing both classifier hyper-parameters and parameters, respectively. Furthermore, the obtained results indicate the promising performance of the proposed textural features and more specifically, those based on co-occurrence matrix of wavelet image representation technique.

  1. Discrimination between normal breast tissue and tumor tissue using CdTe series detector developed for photon-counting mammography

    NASA Astrophysics Data System (ADS)

    Okamoto, Chizuru; Ihori, Akiko; Yamakawa, Tsutomu; Yamamoto, Shuichiro; Okada, Masahiro; Kato, Misa; Nakajima, Ai; Kodera, Yoshie

    2016-03-01

    We propose a new mammography system using a cadmium telluride (CdTe) series photon-counting detector, having high absorption efficiency over a wide energy range. In a previous study, we showed that the use of high X-ray energy in digital mammography is useful from the viewpoint of exposure dose and image quality. In addition, the CdTe series detector can acquire X-ray spectrum information following transmission through a subject. This study focused on the tissue composition identified using spectral information obtained by a new photon-counting detector. Normal breast tissue consists entirely of adipose and glandular tissues. However, it is very difficult to find tumor tissue in the region of glandular tissue via a conventional mammogram, especially in dense breast because the attenuation coefficients of glandular tissue and tumor tissue are very close. As a fundamental examination, we considered a simulation phantom and showed the difference between normal breast tissue and tumor tissue of various thicknesses in a three-dimensional (3D) scatter plot. We were able to discriminate between both types of tissues. In addition, there was a tendency for the distribution to depend on the thickness of the tumor tissue. Thinner tumor tissues were shown to be closer in appearance to normal breast tissue. This study also demonstrated that the difference between these tissues could be made obvious by using a CdTe series detector. We believe that this differentiation is important, and therefore, expect this technology to be applied to new tumor detection systems in the future.

  2. Determination of small field output factors in 6 and 10 MV flattening filter free photon beams using various detectors

    NASA Astrophysics Data System (ADS)

    Masanga, W.; Tangboonduangjit, P.; Khamfongkhruea, C.; Tannanonta, C.

    2016-03-01

    The study aimed to determine appropriate detectors for output factor measurement of small fields in 6 and 10 MV flattening filter free photon beams using five different detectors. Field sizes were varied between 0.6 × 0.6 and 4.0 × 4.0 cm2. An indirect method (daisy-chaining) was applied to normalize the output factors. For the smallest field size, the variations of output factors compared among the detectors were 13%. Exradin A16 had the lowest output factor and increasing in sequence with CC01, microDiamond, microLion and EDGE detectors, respectively, for both energies. The similarity between CC01 and microDiamond output factor values were within 1.6% and 1% for all field sizes of 6 and 10 MV FFF, respectively. EDGE and microLion presented the highest values while ExradinA16 gave lowest values. In conclusion, IBACC01, Exradin A16, microLion, microDiamond and EDGE detectors seem to be the detectors of choices for small field output factor measurement of FFF beams down to 1.6 × 1.6 cm2. However, we could not guarantee which detector is the most suitable for output factor measurement in small field less than 1.6 × 1.6 cm2 of FFF beams. Further studies are required to provide reference information for validation purposes.

  3. Impact of Medicare Shared Savings Program Accountable Care Organizations at Screening Mammography: A Retrospective Cohort Study.

    PubMed

    Narayan, Anand K; Harvey, Susan C; Durand, Daniel J

    2017-02-01

    Purpose To evaluate the impact of accountable care organizations (ACOs) on use of screening mammography in the Medicare Shared Savings Program (MSSP), the largest value-based reimbursement program in U.S.

  4. Ultrasound as an Adjunct to Mammography for Breast Cancer Screening: A Health Technology Assessment

    PubMed Central

    Nikitovic-Jokic, Milica; Tu, Hong Anh; Palimaka, Stefan; Higgins, Caroline; Holubowich, Corinne

    2016-01-01

    Background Screening with mammography can detect breast cancer early, before clinical symptoms appear. Some cancers, however, are not captured with mammography screening alone. Ultrasound has been suggested as a safe adjunct screening tool that can detect breast cancers missed on mammography. We investigated the benefits, harms, cost-effectiveness, and cost burden of ultrasound as an adjunct to mammography compared with mammography alone for screening women at average risk and at high risk for breast cancer. Methods We searched Ovid MEDLINE, Ovid Embase, EBM Reviews, and the NHS Economic Evaluation Database, from January 1998 to June 2015, for evidence of effectiveness, harms, diagnostic accuracy, and cost-effectiveness. Only studies evaluating the use of ultrasound as an adjunct to mammography in the specified populations were included. We also conducted a cost analysis to estimate the costs in Ontario over the next 5 years to fund ultrasound as an adjunct to mammography in breast cancer screening for high-risk women who are contraindicated for MRI, the current standard of care to supplement mammography. Results No studies in average-risk women met the inclusion criteria of the clinical review. We included 5 prospective, paired cohort studies in high-risk women, 4 of which were relevant to the Ontario context. Adjunct ultrasound identified between 2.3 and 5.9 additional breast cancers per 1,000 screens. The average pooled sensitivity of mammography and ultrasound was 53%, a statistically significant increase relative to mammography alone (absolute increase 13%; P < .05). The average pooled specificity of the combined test was 96%, an absolute increase in the false-positive rate of 2% relative to mammography screening alone. The GRADE for this body of evidence was low. Additional annual costs of using breast ultrasound as an adjunct to mammography for high-risk women in Ontario contraindicated for MRI would range from $15,500 to $30,250 in the next 5 years

  5. Dosimetry and kVp standardization for quality assurance of mammography

    NASA Astrophysics Data System (ADS)

    Chu, Chien-Hau; Yuan, Ming-Chen; Huang, Wen-Sheng; Hsieh, Bor-Tsung

    2014-11-01

    Breast cancer mortality rates were significantly reduced in Taiwan after achieving early-stage monitoring with mammography screening. This study establishes an appropriate and traceable calibration infrastructure, which offers calibration services for mammography X-ray quality assurance instrumentation, which is performed clinically on a regular basis. The entrance air kerma, HVL, and kVp of mammography equipment with five different target/filter combinations can be taken as adequate indicators for the level of average glandular dose (AGD). The primary dose standard in mammography uses a free-air ionization chamber to estimate the rate of air kerma. Several correction factors were determined by Monte Carlo simulations and experiments. A secondary kVp standard in mammography is in accordance with the IEC 61676 recommendations. The calibration system of kVp meter uses a high-voltage divider, which is traceable to ITRI primary standard in Taiwan. Dose and kVp verifications were conducted by mammography instruments, which were previously calibrated by NIST and PTB. The evaluation results indicate that the capabilities of this irradiation system met the ISO 4037-1 requirements. The expanded uncertainties (k=2) were 1.03% and 1.6% when the mammography X-ray air kerma rate and kVp meter calibration factors were evaluated using ISO GUM. Experimental verification and a comparison with NIST using transfer ionization chambers yielded differences in calibration factors. Comparison with the PTB using kVp meter indicated a less than 1% difference. The results showed that dose and kVp standards were in reasonable agreement with standard uncertainty. The low uncertainties associated with the obtained results in this work show that the standardization employed can be accurately used for calibration of instrument in mammography in Taiwan.

  6. At what age should screening mammography be recommended for Asian women?

    PubMed

    Tsuchida, Junko; Nagahashi, Masayuki; Rashid, Omar M; Takabe, Kazuaki; Wakai, Toshifumi

    2015-07-01

    Although regular screening mammography has been suggested to be associated with improvements in the relative survival of breast cancer in recent years, the appropriate age to start screening mammography remains controversial. In November 2009, the United States Preventive Service Task Force published updated guidelines for breast cancer, which no longer support routine screening mammography for women aged 40-49 years, but instead, defer the choice of screening in that age group to the patient and physician. The age to begin screening differs between guidelines, including those from the Task Force, the American Cancer Society and the World Health Organization. It remains unclear how this discrepancy impacts patient survival, especially among certain subpopulations. Although the biological characteristics of breast cancer and peak age of incidence differ among different ethnic populations, there have been few reports that evaluate the starting age for screening mammography based on ethnicity. Here, we discuss the benefits and harm of screening mammography in the fifth decade, and re-evaluate the starting age for screening mammography taking ethnicity into account, focusing on the Asian population. Breast cancer incidence peaked in the fifth decade in Asian women, which has been thought to be due to a combination of biological and environmental factors. Previous reports suggest that Asian women in their 40s may receive more benefit and less harm from screening mammography than the age-matched non-Asian US population. Therefore, starting screening mammography at age 40 may be beneficial for women of Asian ethnicity in well-resourced countries, such as Japanese women who reside in Japan.

  7. Adaptive Computer-Assisted Mammography Training for Improved Breast Cancer Screening

    DTIC Science & Technology

    2013-10-01

    disease . The project includes: Observer studies to collect reading data from radiology trainees; Extraction of image features (human- and computer- based...mammography in breast cancer detection and lower mortality associated the disease . 15. SUBJECT TERMS Mammography, radiology, education, user modeling...associated the disease . BODY: Overall progress: Specific aim Expected Actual 1.1 Prepare the database of screening mammograms (year 1, months 1-6

  8. [Advances in research on automatic exposure control of mammography system].

    PubMed

    Wang, Guoyi; Ye, Chengfu; Wu, Haiming; Wang, Tainfu; Zhang, Hong

    2014-12-01

    Mammography imaging is one of the most demanding imaging modalities from the point of view of the bal- ance between image quality (the visibility of small size and/or low contrast structures) and dose (screening of many asymptomatic people). Therefore, since the introduction of the first dedicated mammographic units, many efforts have been directed to seek the best possible image quality while minimizing patient dose. The performance of auto- matic exposure control (AEC) is the manifestation of this demand. The theory of AEC includes exposure detection and optimization and also involves some accomplished methodology. This review presents the development and present situa- tion of spectrum optimization, detector evolution, and the way how to accomplish and evaluate AEC methods.

  9. Do shorter wavelengths improve contrast in optical mammography?

    NASA Astrophysics Data System (ADS)

    Taroni, P.; Pifferi, A.; Torricelli, A.; Spinelli, L.; Danesini, G. M.; Cubeddu, R.

    2004-04-01

    The detection of tumours with time-resolved transmittance imaging relies essentially on blood absorption. Previous theoretical and phantom studies have shown that both contrast and spatial resolution of optical images are affected by the optical properties of the background medium, and high absorption and scattering are generally beneficial. Based on these observations, wavelengths shorter than presently used (680-780 nm) could be profitable for optical mammography. A study was thus performed analysing time-resolved transmittance images at 637, 656, 683 and 785 nm obtained from 26 patients bearing 16 tumours and 15 cysts. The optical contrast proved to increase upon decreasing wavelengths for the detection of cancers in late-gated intensity images, with higher gain in contrast for lesions of smaller size (<1.5 cm diameter). For cysts either a progressive increase or decrease in contrast with wavelength was observed in scattering images.

  10. Photoacoustic mammography capable of simultaneously acquiring photoacoustic and ultrasound images

    NASA Astrophysics Data System (ADS)

    Asao, Yasufumi; Hashizume, Yohei; Suita, Takahiro; Nagae, Ken-ichi; Fukutani, Kazuhiko; Sudo, Yoshiaki; Matsushita, Toshikazu; Kobayashi, Shuichi; Tokiwa, Mariko; Yamaga, Iku; Fakhrejahani, Elham; Torii, Masae; Kawashima, Masahiro; Takada, Masahiro; Kanao, Shotaro; Kataoka, Masako; Shiina, Tsuyoshi; Toi, Masakazu

    2016-11-01

    We have constructed a prototype photoacoustic mammography system (PAM-02) capable of simultaneously acquiring photoacoustic (PA) and ultrasound (US) images. Each PA, US, and fused PA/US image can be acquired over a wide area of the breast using the scanning module of a US transducer, a PA detector, and optical prisms. The resolution of the PA images exhibits improvement from 2 to 1 mm compared to images acquired using our previous prototype. The maximum scan area of PAM-02 is 90 mm along the horizontal axis and 150 mm along the vertical axis. In a phantom experiment, the available depth was at least 45 mm. A representative example of the application of the PAM-02 prototype in clinical research at Kyoto University is presented and shows S-factor images, which are considered an approximation parameter related to hemoglobin saturation of tumor-related blood vessels. We confirmed the applicability of the system for anatomical and biological research.

  11. Measuring output factors of small fields formed by collimator jaws and multileaf collimator using plastic scintillation detectors

    SciTech Connect

    Klein, David M.; Tailor, Ramesh C.; Archambault, Louis; Wang, Lilie; Therriault-Proulx, Francois; Beddar, A. Sam

    2010-10-15

    Purpose: As the practice of using high-energy photon beams to create therapeutic radiation fields of subcentimeter dimensions (as in intensity-modulated radiotherapy or stereotactic radiosurgery) grows, so too does the need for accurate verification of beam output at these small fields in which standard practices of dose verification break down. This study investigates small-field output factors measured using a small plastic scintillation detector (PSD), as well as a 0.01 cm{sup 3} ionization chamber. Specifically, output factors were measured with both detectors using small fields that were defined by either the X-Y collimator jaws or the multileaf collimator (MLC). Methods: A PSD of 0.5 mm diameter and 2 mm length was irradiated with 6 and 18 MV linac beams. The PSD was positioned vertically at a source-to-axis distance of 100 cm, at 10 cm depth in a water phantom, and irradiated with fields ranging in size from 0.5x0.5 to 10x10 cm{sup 2}. The field sizes were defined either by the collimator jaws alone or by a MLC alone. The MLC fields were constructed in two ways: with the closed leaves (i.e., those leaves that were not opened to define the square field) meeting at either the field center line or at a 4 cm offset from the center line. Scintillation light was recorded using a CCD camera and an estimation of error in the median-filtered signals was made using the bootstrapping technique. Measurements were made using a CC01 ionization chamber under conditions identical to those used for the PSD. Results: Output factors measured by the PSD showed close agreement with those measured using the ionization chamber for field sizes of 2.0x2.0 cm{sup 2} and above. At smaller field sizes, the PSD obtained output factors as much as 15% higher than those found using the ionization chamber by 0.6x0.6 cm{sup 2} jaw-defined fields. Output factors measured with no offset of the closed MLC leaves were as much as 20% higher than those measured using a 4 cm leaf offset

  12. Four Principles to Consider Before Advising Women on Screening Mammography.

    PubMed

    Keen, John D; Jørgensen, Karsten J

    2015-11-01

    This article reviews four important screening principles applicable to screening mammography in order to facilitate informed choice. The first principle is that screening may help, hurt, or have no effect. In order to reduce mortality and mastectomy rates, screening must reduce the rate of advanced disease, which likely has not happened. Through overdiagnosis, screening produces substantial harm by increasing both lumpectomy and mastectomy rates, which offsets the often-promised benefit of less invasive therapy. Next, all-cause mortality is the most reliable way to measure the efficacy of a screening intervention. Disease-specific mortality is biased due to difficulties in attribution of cause of death and to increased mortality due to overdiagnosis and the resulting overtreatment with radiotherapy and chemotherapy. To enhance participation, the benefit from screening is often presented in relative instead of absolute terms. Third, some screening statistics must be interpreted with caution. Increased survival time and the percentage of early-stage tumors at detection sound plausible, but are affected by lead-time and length biases. In addition, analyses that only include women who attend screening cannot reliably correct for selection bias. The final principle is that accounting for tumor biology is important for accurate estimates of lead time, and the potential benefit from screening. Since "early detection" is actually late in a tumor's lifetime, the time window when screen detection might extend a woman's life is narrow, as many tumors that can form metastases will already have done so. Instead of encouraging screening mammography, physicians should help women make an informed decision as with any medical intervention.

  13. Geographic Disparities in Mammography Capacity in the South: A Longitudinal Assessment of Supply and Demand

    PubMed Central

    Eberth, Jan M; Eschbach, Karl; Morris, Jeffrey S; Nguyen, Hoang T; Hossain, Md Monir; Elting, Linda S

    2014-01-01

    ObjectiveStudies have shown that there is sufficient availability of mammography; however, little is known about geographic variation in capacity. The purpose of this study was to determine the locations and extent of over/undersupply of mammography in 14 southern states from 2002 to 2008. Data SourcesMammography facility data were collected from the U.S. Food and Drug Administration (FDA). Population estimates, used to estimate the potential demand for mammography, were obtained from GeoLytics Inc. Study DesignUsing the two-step floating catchment area method, we calculated spatial accessibility at the block group level and categorized the resulting index to represent the extent of under/oversupply relative to the potential demand. Principal FindingsResults show decreasing availability of mammography over time. The extent of over/undersupply varied significantly across the South. Reductions in capacity occurred primarily in areas with an oversupply of machines, resulting in a 68 percent decrease in the percent of women living in excess capacity areas from 2002 to 2008. The percent of women living in poor capacity areas rose by 10 percent from 2002 to 2008. ConclusionsOur study found decreasing mammography availability and capacity over time, with substantial variation across states. This information can assist providers and policy makers in their business planning and resource allocation decisions. PMID:23829179

  14. Correlation between molybdenum target mammography signs and pathological prognostic factors of breast cancer.

    PubMed

    Zhang, Y; Ma, A D; Jia, H X

    2016-01-01

    This study explores the correlation between molybdenum target (mo-target) mammography signs and pathological prognostic factors of breast cancer. We selected 320 breast cancer patients who were treated between January 2014 and January 2016; using single-factor and multiple-factor logistic regression method, we made correlation analysis on their clinical features, pathological features and mo-target mammography signs. Among mo-target mammography signs, lumps accompanied with calcification and blurry edge were associated with high histologic grades; lumps accompanied with calcification and clear edge were associated with Ki-67 positive; compared with the patients who had lumps with non-stellate edges, positive rates of estrogen receptor (ER) and progesterone receptor (PR) were significantly higher for the patients who had lumps with stellate edges (p < 0.01), while positive rate of human epidermal growth factor receptor-2 (HER-2) and tumor proliferative activity were significantly lower (p < 0.05, p < 0.01). According to the study, we can conclude that mo-target mammography signs mainly include lumps and calcification. Mo-target mammography can improve the accuracy of diagnosis and reduce misdiagnosis or missed diagnosis. Part of mo-target mammography signs are associated with clinical pathology prognostic factors; by grasping the relation, breast cancer patient conditions are expected to be relieved.

  15. Keeping mammography referral appointments: motivation, health beliefs, and access barriers experienced by older minority women.

    PubMed

    Bernstein, J; Mutschler, P; Bernstein, E

    2000-01-01

    Older women of color tend to have much lower rates of regular mammography screening for breast cancer than younger Caucasian women; yet, they have higher rates of mortality. This study was designed to increase mammography rates among inner-city women aged 50 years or older. Another goal was to investigate differences in mammography utilization related to race/ethnicity and language after barriers associated with cost and the difficulty of making an appointment are removed. A peer delivered intervention, which consisted of interview, mammography referral, and the scheduling of a next-day appointment, was conducted among a convenience sample of 151 culturally and racially diverse older women through a primary care referral project operating within an urban emergency department (ED). A brief motivational interview and mammography referral at the time of an ED visit, including scheduling of a next-day no cost appointment, was followed by a cross-sectional telephone survey of utilization and motivating and hindering factors. Follow-up was achieved with 96 women (66%). Fifty-eight women (60%) had a post-intervention mammogram; of those, 69% were first time users. More than 90% planned a repeat mammogram the following year. Of the 27 who did not receive a mammogram, 21 (77%) requested a "second try" appointment. These findings demonstrate that an interactive intervention among older women of color has the potential to dramatically increase mammography rates.

  16. TU-F-201-04: Applications in Small Fields and Proton Beams

    SciTech Connect

    Das, I.

    2015-06-15

    Since the introduction of radiochromic films (RCF) for radiation dosimetry, the scope of RCF dosimetry has expanded steadily to include many medical applications, such as radiation therapy and diagnostic radiology. The AAPM Task Group (TG) 55 published a report on the recommendations for RCF dosimetry in 1998. As the technology is advancing rapidly, and its routine clinical use is expanding, TG 235 has been formed to provide an update to TG-55 on radiochromic film dosimetry. RCF dosimetry applications in clinical radiotherapy have become even more widespread, expanding from primarily brachytherapy and radiosurgery applications, and gravitating towards (but not limited to) external beam therapy (photon, electron and protons), such as quality assurance for IMRT, VMAT, Tomotherapy, SRS/SRT, and SBRT. In addition, RCF applications now extend to measurements of radiation dose in particle beams and patients undergoing medical exams, especially fluoroscopically guided interventional procedures and CT. The densitometers/scanners used for RCF dosimetry have also evolved from the He-Ne laser scanner to CCD-based scanners, including roller-based scanner, light box-based digital camera, and flatbed color scanner. More recently, multichannel RCF dosimetry introduced a new paradigm for external beam dose QA for its high accuracy and efficiency. This course covers in detail the recent advancements in RCF dosimetry. Learning Objectives: Introduce the paradigm shift on multichannel film dosimetry Outline the procedures to achieve accurate dosimetry with a RCF dosimetry system Provide comprehensive guidelines on RCF dosimetry for various clinical applications One of the speakers has a research agreement from Ashland Inc., the manufacturer of Gafchromic film.

  17. Comparison of the Mammography, Contrast-Enhanced Spectral Mammography and Ultrasonography in a Group of 116 patients.

    PubMed

    Luczyńska, Elzbieta; Heinze, Sylwia; Adamczyk, Agnieszka; Rys, Janusz; Mitus, Jerzy W; Hendrick, Edward

    2016-08-01

    Mammography (MG) is the gold-standard in breast cancer detection - the only method documented to reduce breast cancer mortality. Breast ultrasound (US) has been shown to increase sensitivity to breast cancers in screening women with dense breasts. Contrast-enhanced spectral mammography (CESM) is a novel technique intensively developed in the last few years. The goal of this study was to compare the sensitivity, specificity and accuracy of MG, US and CESM in detecting malignant breast lesions. The study included 116 patients. All patients were symptomatic and underwent MG, US and CESM. A radiologist with 20 years of experience in US and MG breast imaging and 1 year of experience in CESM reviewed images acquired in each of the three modalities separately, within an interval of 14-30 days. All identified lesions were confirmed at core biopsy. BI-RADS classifications on US, MG and CESM were compared to histopathology. MG, CESM and US were compared among 116 patients with 137 lesions encountered. Sensitivity of CESM was 100%, significantly higher than that of MG (90%, p<0.004) or US (92%, p<0.01). CESM accuracy was 78%, also higher than MG (69%, p<0.004) and US (70%, p=0.03). There was no statistically significant difference between AUCs for CESM and US (both 0.83). The AUCs of both US and CESM, however, were significantly larger than that of MG (p<0.0004 for each). CESM permitted better detection of malignant lesions than both MG and US, read individually. CESM found lesion enhancement in some benign lesions, as well, yielding a rate of false-positive diagnoses similar to that of MG and US.

  18. Investigation of the Z-axis resolution of breast tomosynthesis mammography systems

    NASA Astrophysics Data System (ADS)

    Zhang, Yiheng; Chan, Heang-Ping; Sahiner, Berkman; Wei, Jun; Ge, Jun; Hadjiiski, Lubomir M.; Zhou, Chuan

    2007-03-01

    Digital Tomosynthesis Mammography (DTM) is a promising modality that can improve breast cancer detection. DTM acquires low-dose mammograms at a number of projection angles over a limited angular range and reconstructs the 3D breast volume. DTM can provide depth information to separate overlapping breast tissues occurred in conventional mammograms, thereby facilitating detection of subtle lesions. In this work, we investigated the impact of the imaging parameters and reconstruction methods on the Z-axis resolution in DTM systems. The Z-axis resolution represents the ability of the DTM system to distinguish adjacent objects along the depth direction. A DTM system with variable image acquisition parameters was modeled. In this preliminary study, a computer phantom containing a high-density point object embedded in an air volume was used. We simulated a range of DTM conditions by generating an appropriate number of PV images in 3° increments covering a total tomosynthesis angle from +/-15° to +/-30°. The Simultaneous Algebraic Reconstruction Technique (SART) was used for reconstruction of the imaged volume from the noise-free projection data and the results were compared to those of back-projection method. Vertical line profiles along the Z-axis and through the object center were extracted from the reconstructed volume and the full-width-at-half-maximum (FWHM) of the normalized intensity profile was used to evaluate the Z-axis resolution. Preliminary results demonstrated that while the Z-axis resolution remains almost constant as a function of depth within a 5-cm-thick volume, it is strongly affected by the PV angular range such that the depth resolution improves with increasing total tomosynthesis angle. The depth resolution also depends on the reconstruction algorithm employed; the SART method is superior to the simple back-projection method in terms of depth resolution.

  19. Parameter optimization of parenchymal texture analysis for prediction of false-positive recalls from screening mammography

    NASA Astrophysics Data System (ADS)

    Ray, Shonket; Keller, Brad M.; Chen, Jinbo; Conant, Emily F.; Kontos, Despina

    2016-03-01

    This work details a methodology to obtain optimal parameter values for a locally-adaptive texture analysis algorithm that extracts mammographic texture features representative of breast parenchymal complexity for predicting falsepositive (FP) recalls from breast cancer screening with digital mammography. The algorithm has two components: (1) adaptive selection of localized regions of interest (ROIs) and (2) Haralick texture feature extraction via Gray- Level Co-Occurrence Matrices (GLCM). The following parameters were systematically varied: mammographic views used, upper limit of the ROI window size used for adaptive ROI selection, GLCM distance offsets, and gray levels (binning) used for feature extraction. Each iteration per parameter set had logistic regression with stepwise feature selection performed on a clinical screening cohort of 474 non-recalled women and 68 FP recalled women; FP recall prediction was evaluated using area under the curve (AUC) of the receiver operating characteristic (ROC) and associations between the extracted features and FP recall were assessed via odds ratios (OR). A default instance of mediolateral (MLO) view, upper ROI size limit of 143.36 mm (2048 pixels2), GLCM distance offset combination range of 0.07 to 0.84 mm (1 to 12 pixels) and 16 GLCM gray levels was set. The highest ROC performance value of AUC=0.77 [95% confidence intervals: 0.71-0.83] was obtained at three specific instances: the default instance, upper ROI window equal to 17.92 mm (256 pixels2), and gray levels set to 128. The texture feature of sum average was chosen as a statistically significant (p<0.05) predictor and associated with higher odds of FP recall for 12 out of 14 total instances.

  20. Quantification of breast density with dual energy mammography: a simulation study.

    PubMed

    Ducote, Justin L; Molloi, Sabee

    2008-12-01

    Breast density, the percentage of glandular breast tissue, has been identified as an important yet underutilized risk factor in the development of breast cancer. A quantitative method to measure breast density with dual energy imaging was investigated using a computer simulation model. Two configurations to measure breast density were evaluated: the usage of monoenergetic beams and an ideal detector, and the usage of polyenergetic beams with spectra from a tungsten anode x-ray tube with a detector modeled after a digital mammography system. The simulation model calculated the mean glandular dose necessary to quantify the variability of breast density to within 1/3%. The breast was modeled as a semicircle 10 cm in radius with equal homogenous thicknesses of adipose and glandular tissues. Breast thicknesses were considered in the range of 2-10 cm and energies in the range of 10-150 keV for the two monoenergetic beams, and 20-150 kVp for spectra with a tungsten anode x-ray tube. For a 4.2 cm breast thickness, the required mean glandular doses were 0.183 microGy for two monoenergetic beams at 19 and 71 keV, and 9.85 microGy for two polyenergetic spectra from a tungsten anode at 32 and 96 kVp with beam filtrations of 50 microm Rh and 300 microm Cu for the low and high energy beams, respectively. The results suggest that for either configuration, breast density can be precisely measured with dual energy imaging requiring only a small amount of additional dose to the breast. The possibility of using a standard screening mammogram as the low energy image is also discussed.

  1. Quantification of breast density with dual energy mammography: A simulation study

    SciTech Connect

    Ducote, Justin L.; Molloi, Sabee

    2008-12-15

    Breast density, the percentage of glandular breast tissue, has been identified as an important yet underutilized risk factor in the development of breast cancer. A quantitative method to measure breast density with dual energy imaging was investigated using a computer simulation model. Two configurations to measure breast density were evaluated: the usage of monoenergetic beams and an ideal detector, and the usage of polyenergetic beams with spectra from a tungsten anode x-ray tube with a detector modeled after a digital mammography system. The simulation model calculated the mean glandular dose necessary to quantify the variability of breast density to within (1/3)%. The breast was modeled as a semicircle 10 cm in radius with equal homogenous thicknesses of adipose and glandular tissues. Breast thicknesses were considered in the range of 2-10 cm and energies in the range of 10-150 keV for the two monoenergetic beams, and 20-150 kVp for spectra with a tungsten anode x-ray tube. For a 4.2 cm breast thickness, the required mean glandular doses were 0.183 {mu}Gy for two monoenergetic beams at 19 and 71 keV, and 9.85 {mu}Gy for two polyenergetic spectra from a tungsten anode at 32 and 96 kVp with beam filtrations of 50 {mu}m Rh and 300 {mu}m Cu for the low and high energy beams, respectively. The results suggest that for either configuration, breast density can be precisely measured with dual energy imaging requiring only a small amount of additional dose to the breast. The possibility of using a standard screening mammogram as the low energy image is also discussed.

  2. Quantification of breast density with dual energy mammography: A simulation study

    PubMed Central

    Ducote, Justin L.; Molloi, Sabee

    2008-01-01

    Breast density, the percentage of glandular breast tissue, has been identified as an important yet underutilized risk factor in the development of breast cancer. A quantitative method to measure breast density with dual energy imaging was investigated using a computer simulation model. Two configurations to measure breast density were evaluated: the usage of monoenergetic beams and an ideal detector, and the usage of polyenergetic beams with spectra from a tungsten anode x-ray tube with a detector modeled after a digital mammography system. The simulation model calculated the mean glandular dose necessary to quantify the variability of breast density to within 1∕3%. The breast was modeled as a semicircle 10 cm in radius with equal homogenous thicknesses of adipose and glandular tissues. Breast thicknesses were considered in the range of 2–10 cm and energies in the range of 10–150 keV for the two monoenergetic beams, and 20–150 kVp for spectra with a tungsten anode x-ray tube. For a 4.2 cm breast thickness, the required mean glandular doses were 0.183 μGy for two monoenergetic beams at 19 and 71 keV, and 9.85 μGy for two polyenergetic spectra from a tungsten anode at 32 and 96 kVp with beam filtrations of 50 μm Rh and 300 μm Cu for the low and high energy beams, respectively. The results suggest that for either configuration, breast density can be precisely measured with dual energy imaging requiring only a small amount of additional dose to the breast. The possibility of using a standard screening mammogram as the low energy image is also discussed. PMID:19175100

  3. Evaluating a tailored intervention to increase screening mammography in an urban area.

    PubMed Central

    Allen, Bruce; Bazargan-Hejazi, Shahrzad

    2005-01-01

    METHOD: The study was conducted over a four-year period, 1996 and 2000. Participants were recruited using Computer Assisted Telephone Interviewing (CATI) software and random-digit dialing (RDD). Study eligibility criteria included living in the King/Drew Medical Center service area in Los Angeles, having an operable telephone, being female > or = 40 years old and not having had a screening mammogram in the past year. Four-hundred-thirty respondents were randomly assigned to the intervention and comparison groups. English and Spanish focus-group-tested tailored interventions were administered telephonically by trained interviewers. African Americans and Latinas constituted 83.0% of the sample at assignment and 83.8% at six-month follow-up, which is representative of the study area. RESULTS: The main outcome variable of interest in this study was having a screening mammogram during the time interval between baseline and the six-month follow-up assessment. Multiple logistic regressions that revealed factors predicting the outcome variable included: 1) age (p < or = 0.05, OR=2.22, CI 0.98-5.0); 2) study group (p < or = 0.05, OR=1.76, CI 1.06-2.92); 3) prior mammograms (p < or = 0.05, O0R=2.51, 1.39-4.56); and 4) and knowledge of the age when a woman should begin getting mammograms on a regular basis (p < or = 0.05, OR=0.55, 0.33-0.92). CONCLUSION: Tailored telephone counseling increased the instances of screening mammograms by nearly 8% in the intervention group at follow-up. The results of this study confirm previous findings regarding the impact of structural and behavioral factors related to screening mammography. PMID:16353657

  4. DICOM organ dose does not accurately represent calculated dose in mammography

    NASA Astrophysics Data System (ADS)

    Suleiman, Moayyad E.; Brennan, Patrick C.; McEntee, Mark F.

    2016-03-01

    This study aims to analyze the agreement between the mean glandular dose estimated by the mammography unit (organ dose) and mean glandular dose calculated using Dance et al published method (calculated dose). Anonymised digital mammograms from 50 BreastScreen NSW centers were downloaded and exposure information required for the calculation of dose was extracted from the DICOM header along with the organ dose estimated by the system. Data from quality assurance annual tests for the included centers were collected and used to calculate the mean glandular dose for each mammogram. Bland-Altman analysis and a two-tailed paired t-test were used to study the agreement between calculated and organ dose and the significance of any differences. A total of 27,869 dose points from 40 centers were included in the study, mean calculated dose and mean organ dose (+/- standard deviation) were 1.47 (+/-0.66) and 1.38 (+/-0.56) mGy respectively. A statistically significant 0.09 mGy bias (t = 69.25; p<0.0001) with 95% limits of agreement between calculated and organ doses ranging from -0.34 and 0.52 were shown by Bland-Altman analysis, which indicates a small yet highly significant difference between the two means. The use of organ dose for dose audits is done at the risk of over or underestimating the calculated dose, hence, further work is needed to identify the causal agents for differences between organ and calculated doses and to generate a correction factor for organ dose.

  5. Comparison of volumetric breast density estimations from mammography and thorax CT.

    PubMed

    Geeraert, N; Klausz, R; Cockmartin, L; Muller, S; Bosmans, H; Bloch, I

    2014-08-07

    Breast density has become an important issue in current breast cancer screening, both as a recognized risk factor for breast cancer and by decreasing screening efficiency by the masking effect. Different qualitative and quantitative methods have been proposed to evaluate area-based breast density and volumetric breast density (VBD). We propose a validation method comparing the computation of VBD obtained from digital mammographic images (VBDMX) with the computation of VBD from thorax CT images (VBDCT). We computed VBDMX by applying a conversion function to the pixel values in the mammographic images, based on models determined from images of breast equivalent material. VBDCT is computed from the average Hounsfield Unit (HU) over the manually delineated breast volume in the CT images. This average HU is then compared to the HU of adipose and fibroglandular tissues from patient images. The VBDMX method was applied to 663 mammographic patient images taken on two Siemens Inspiration (hospL) and one GE Senographe Essential (hospJ). For the comparison study, we collected images from patients who had a thorax CT and a mammography screening exam within the same year. In total, thorax CT images corresponding to 40 breasts (hospL) and 47 breasts (hospJ) were retrieved. Averaged over the 663 mammographic images the median VBDMX was 14.7% . The density distribution and the inverse correlation between VBDMX and breast thickness were found as expected. The average difference between VBDMX and VBDCT is smaller for hospJ (4%) than for hospL (10%). This study shows the possibility to compare VBDMX with the VBD from thorax CT exams, without additional examinations. In spite of the limitations caused by poorly defined breast limits, the calibration of mammographic images to local VBD provides opportunities for further quantitative evaluations.

  6. Comparison of volumetric breast density estimations from mammography and thorax CT

    NASA Astrophysics Data System (ADS)

    Geeraert, N.; Klausz, R.; Cockmartin, L.; Muller, S.; Bosmans, H.; Bloch, I.

    2014-08-01

    Breast density has become an important issue in current breast cancer screening, both as a recognized risk factor for breast cancer and by decreasing screening efficiency by the masking effect. Different qualitative and quantitative methods have been proposed to evaluate area-based breast density and volumetric breast density (VBD). We propose a validation method comparing the computation of VBD obtained from digital mammographic images (VBDMX) with the computation of VBD from thorax CT images (VBDCT). We computed VBDMX by applying a conversion function to the pixel values in the mammographic images, based on models determined from images of breast equivalent material. VBDCT is computed from the average Hounsfield Unit (HU) over the manually delineated breast volume in the CT images. This average HU is then compared to the HU of adipose and fibroglandular tissues from patient images. The VBDMX method was applied to 663 mammographic patient images taken on two Siemens Inspiration (hospL) and one GE Senographe Essential (hospJ). For the comparison study, we collected images from patients who had a thorax CT and a mammography screening exam within the same year. In total, thorax CT images corresponding to 40 breasts (hospL) and 47 breasts (hospJ) were retrieved. Averaged over the 663 mammographic images the median VBDMX was 14.7% . The density distribution and the inverse correlation between VBDMX and breast thickness were found as expected. The average difference between VBDMX and VBDCT is smaller for hospJ (4%) than for hospL (10%). This study shows the possibility to compare VBDMX with the VBD from thorax CT exams, without additional examinations. In spite of the limitations caused by poorly defined breast limits, the calibration of mammographic images to local VBD provides opportunities for further quantitative evaluations.

  7. The interplay of attention economics and computer-aided detection marks in screening mammography

    NASA Astrophysics Data System (ADS)

    Schwartz, Tayler M.; Sridharan, Radhika; Wei, Wei; Lukyanchenko, Olga; Geiser, William; Whitman, Gary J.; Haygood, Tamara Miner

    2016-03-01

    Introduction: According to attention economists, overabundant information leads to decreased attention for individual pieces of information. Computer-aided detection (CAD) alerts radiologists to findings potentially associated with breast cancer but is notorious for creating an abundance of false-positive marks. We suspected that increased CAD marks do not lengthen mammogram interpretation time, as radiologists will selectively disregard these marks when present in larger numbers. We explore the relevance of attention economics in mammography by examining how the number of CAD marks affects interpretation time. Methods: We performed a retrospective review of bilateral digital screening mammograms obtained between January 1, 2011 and February 28, 2014, using only weekend interpretations to decrease distractions and the likelihood of trainee participation. We stratified data according to reader and used ANOVA to assess the relationship between number of CAD marks and interpretation time. Results: Ten radiologists, with median experience after residency of 12.5 years (range 6 to 24,) interpreted 1849 mammograms. When accounting for number of images, Breast Imaging Reporting and Data System category, and breast density, increasing numbers of CAD marks was correlated with longer interpretation time only for the three radiologists with the fewest years of experience (median 7 years.) Conclusion: For the 7 most experienced readers, increasing CAD marks did not lengthen interpretation time. We surmise that as CAD marks increase, the attention given to individual marks decreases. Experienced radiologists may rapidly dismiss larger numbers of CAD marks as false-positive, having learned that devoting extra attention to such marks does not improve clinical detection.

  8. Relationship Between Perceived Risk and Physician Recommendation and Repeat Mammography in the Female Population in Tehran, Iran.

    PubMed

    Moshki, Mahdi; Taymoori, Parvaneh; Khodamoradi, Sahmireh; Roshani, Daem

    2016-01-01

    Iranian women are at high risk of low compliance with repeat mammography due to a lack of awareness about breast cancer, negative previous experiences, cultural beliefs, and no regular visits to a physician. Thus research is needed to explore factors associated with repeated mammography participation. Applying the concept of perceived risk as the guiding model, this study aimed to test the fit and strength of the relationship between perceived risk and physician recommendation in explaining repeat mammography. A total of 601 women, aged 50 years and older referred to mammography centers in region 6, were recruited via a convenience sampling method. Using path analysis, family history of breast cancer and other types of cancer were modeled as antecedent perceived risk, and physician recommendation and knowledge were modeled as an antecedent of the number of mammography visits. The model explained 49% of the variance in repeat mammography. The two factors of physician recommendation and breast self-examination had significant direct effects (P < 0.05) on repeat mammography. Perceived risk, knowledge, and family history of breast cancer had significant indirect effects on repeat mammography through physician recommendation. The results of this study provide a background for further research and interventions not only on Iranian women but also on similar cultural groups and immigrants who have been neglected to date in the mammography literature.

  9. Evaluation of the Relationship Between Family History of Breast Cancer and Risk Perception and Impacts on Repetition of Mammography.

    PubMed

    Khoshravesh, Sahar; Taymoori, Parvaneh; Roshani, Daem

    2016-01-01

    Since the mean age of breast cancer in women living in developing countries, compared with those in developed countries, is lower by about 10 years, repetition of mammography can play an important role in reducing morbidity and mortality. Hence, this study aimed to investigate the relationship between family history of breast cancer and risk perception and its impact on repetition of mammography. In this cross-sectional study, 1,507 women aged 50 years and older, referred to the mammography center of Regions 1 and 6 in Tehran, Iran, were enrolled. Data were collected using a self-report questionnaire and analyzed using SPSS and LISREL. According to our findings, knowledge about the time interval of mammography was found to have the highest correlation with repetition of mammography (r =0.4). Among the demographic variables, marital status (β= -0.1) and family history of breast cancer (β=0.1) had the most direct and significant impact on repetition of mammography (P <0.05). Among the other variables studied, knowledge (β=-0.5) had the highest direct and significant impact on repetition of mammography (P <0.05). Family history of breast cancer was one of the predictors of repetition of mammography, but the results did not prove any relationship with risk perception. Further studies are needed to assess the effect of risk perception and knowledge about time interval on the initiation and continuation of mammography.

  10. A comparison of small-field tissue phantom ratio data generation methods for an Elekta Agility 6 MV photon beam.

    PubMed

    Richmond, Neil; Brackenridge, Robert

    2014-01-01

    Tissue-phantom ratios (TPRs) are a common dosimetric quantity used to describe the change in dose with depth in tissue. These can be challenging and time consuming to measure. The conversion of percentage depth dose (PDD) data using standard formulae is widely employed as an alternative method in generating TPR. However, the applicability of these formulae for small fields has been questioned in the literature. Functional representation has also been proposed for small-field TPR production. This article compares measured TPR data for small 6 MV photon fields against that generated by conversion of PDD using standard formulae to assess the efficacy of the conversion data. By functionally fitting the measured TPR data for square fields greater than 4cm in length, the TPR curves for smaller fields are generated and compared with measurements. TPRs and PDDs were measured in a water tank for a range of square field sizes. The PDDs were converted to TPRs using standard formulae. TPRs for fields of 4 × 4cm(2) and larger were used to create functional fits. The parameterization coefficients were used to construct extrapolated TPR curves for 1 × 1 cm(2), 2 × 2-cm(2), and 3 × 3-cm(2) fields. The TPR data generated using standard formulae were in excellent agreement with direct TPR measurements. The TPR data for 1 × 1-cm(2), 2 × 2-cm(2), and 3 × 3-cm(2) fields created by extrapolation of the larger field functional fits gave inaccurate initial results. The corresponding mean differences for the 3 fields were 4.0%, 2.0%, and 0.9%. Generation of TPR data using a standard PDD-conversion methodology has been shown to give good agreement with our directly measured data for small fields. However, extrapolation of TPR data using the functional fit to fields of 4 × 4cm(2) or larger resulted in generation of TPR curves that did not compare well with the measured data.

  11. Perspectives on Mammography After Receipt of Secondary Screening Due to a False Positive

    PubMed Central

    Siminoff, Laura A.

    2014-01-01

    BACKGROUND The utility of mammography screening as an efficacious tool for early detection is being contested due to the risk of potential harms including psychological distress and exposure to unnecessary procedures associated with FPs and over-diagnosis. Yet there is little research regarding women’s experiences, values or preferences for participating in mammography programs. Our aim was to explore women’s actual experiences of a FP mammography screen and their perceptions of the value, risks and benefits given their recent experience. METHODS We conducted semi-structured interviews with 40 women who experienced a recent FP mammogram. Interviews were recorded and transcribed verbatim. A directed content analysis was used to identify and explore primary themes. Knowledge of breast cancer risk was also assessed. FINDINGS Receiving a FP mammography screen generated significant worry among 60% (n=24) of women. Yet 70% maintained that mammography screening was necessary despite the worry incurred. Women also described the experience as stimulating greater interest in additional cancer prevention activities (32.5%; n=13) and one third discussed needing more information about the risks and benefits of mammography screening. Less than one quarter of women (22.5%; n=9) correctly identified a women’s lifetime risk of developing breast cancer, 20% (n=8) overestimated and 57.5% (n=23) underestimated this risk. CONCLUSION Women reported needing more information about the risks and benefits of mammography screening but also considered FPs an acceptable risk. Further, our results suggest that breast cancer screening programs may provide a unique opportunity to deliver additional breast cancer prevention interventions. PMID:25648490

  12. Validating self-reported mammography use in vulnerable communities: findings and recommendations

    PubMed Central

    Allgood, Kristi L.; Rauscher, Garth H.; Whitman, Steven; Vasquez-Jones, Giselle; Shah, Ami M.

    2014-01-01

    Background Most health surveys ask women whether they have had a recent mammogram, all of which report mammography use (past two years) at about 70–80% regardless of race or residence. We examined the potential extent of over-reporting of mammography use in low income African-American and Latina women, and whether self-report inaccuracies might bias estimated associations between patient characteristics and mammography use. Methods Using venue based sampling in two poor communities on the west side of Chicago, we asked eligible women living in two west side communities of Chicago to complete a survey about breast health (n=2,200) and to provide consent to view their medical record. Of the n=1,909 women who screened eligible for medical record review, n=1,566 consented (82%). We obtained medical records of all women who provided both permission and a valid local mammography facility (n=1,221). We compared the self-reported responses from the survey to the imaging reports found in the medical record (documented). To account for missing data we conducted multiple imputations for key demographic variables and report standard measures of accuracy. Results Although 73% of women self-reported a mammogram in the last 2 years, only 45% of self-reports were documented. Over-reporting of mammography use was observed for all three ethnic groups. Conclusions These results suggest considerable over-estimation of prevalence of use in these vulnerable populations. Impact Relying on known faulty self-reported mammography data as a measure of mammography use provides an overly optimistic picture of utilization, a problem that may be exacerbated in vulnerable minority communities. PMID:24859870

  13. Mammography use among older women of seven Latin American and Caribbean cities

    PubMed Central

    Reyes-Ortiz, Carlos A.; Freeman, Jean L.; Peláez, Martha; Markides, Kyriakos S.; Goodwin, James S.

    2007-01-01

    Background To describe the prevalence of mammography use, and to estimate its association with sociodemographics. Methods A sample of 6207 women aged 60 and older from the first interview of Health, Well-Being and Aging in Latin America and the Caribbean Study (SABE) in seven cities (Buenos Aires, Bridgetown, Havana, Mexico, Montevideo, Santiago, and Sao Paulo). The outcome was reporting a mammogram within the last 2 years. Results Prevalence of mammography use ranged from 9.8% in Havana to 34.4% in Sao Paulo. Independent predictors of mammography use across cities were older age (lowest odds ratio [OR] = 0.92, 95% confidence interval [CI] 0.89–0.95), higher education (highest OR = 1.14, 95% CI 1.08–1.20), public health insurance (lowest OR = 0.28, 95% CI 0.11–0.76), or no insurance (lowest OR = 0.08, 95% CI 0.02–0.34) compared with private insurance. In a combined sample of six cities, higher education was associated with higher mammography use, but older age and insurance (public: OR = 0.54, 95% CI 0.45–0.65; no insurance: OR = 0.30, 95% CI 0.23–0.40; compared with private insurance) were associated with lower mammography use. Conclusions Prevalence of mammography use across cities was lower than that reported for Hispanic populations in the US. In the overall sample, mammography use was increased in highly educated people and decreased in people without insurance. PMID:16563480

  14. Is Short-Interval Mammography Necessary After Breast Conservation Surgery and Radiation Treatment in Breast Cancer Patients?

    SciTech Connect

    Hymas, Richard V.; Gaffney, David K.; Parkinson, Brett T.; Belnap, Thomas W.; Sause, William T.

    2012-06-01

    Purpose: The optimum timing and frequency of mammography in breast cancer patients after breast-conserving therapy (BCT) are controversial. The American Society of Clinical Oncology recommends the first posttreatment mammogram 1 year after diagnosis but no earlier than 6 months after completion of radiotherapy. The National Comprehensive Cancer Network recommends annual mammography. Intermountain Healthcare currently follows a more frequent mammography schedule during the first 2 years in BCT patients. This retrospective study was undertaken to determine the cancer yield mammography during the first 2 years after BCT. Methods and Materials: 1,435 patients received BCT at Intermountain Healthcare between 2003 and 2007, inclusive. Twenty-three patients had bilateral breast cancer (1,458 total breasts). Patients were followed up for 24 months after diagnosis. The 1- and 2-year mammography yields were determined and compared with those of the general screening population. Results: 1,079 breasts had mammography at less than 1 year, and two ipsilateral recurrences (both noninvasive) were identified; 1,219 breasts had mammography during the second year, and nine recurrences (three invasive, six noninvasive) were identified. Of the 11 ipsilateral recurrences during the study, three presented with symptoms and eight were identified by mammography alone. The mammography yield was 1.9 cancers per 1,000 breasts the first year and 4.9 per 1,000 the second year. Conclusions: These data demonstrate that the mammography yield during the first 2 years after BCT is not greater than that in the general population, and they support the policy for initiating followup mammography at 1 year after BCT.

  15. Women with abnormal screening mammography lost to follow-up

    PubMed Central

    Kuo, Chia-Sheng; Chen, Guan-Ru; Hung, Shou-Hung; Liu, Yi-Lien; Huang, Kuo-Chin; Cheng, Shao-Yi

    2016-01-01

    Abstract Breast cancer has the highest incidence among all cancers for women in Taiwan. The current screening policy in Taiwan suggested a biennial mammography for all women 40 to 69 years of age. A recommendation for additional testing is recommended for women with a BI-RADS result of 0 or 4; a request made via postal mail. Approximately 20% of high-risk patients do not receive additional follow-up. Therefore, we aimed to explore the causes of these patients being lost to follow-up, despite an abnormal mammogram. Two questionnaires were designed separately according to the conceptual framework of the Health Belief Model. Study participants, women who received a screening mammography at the National Taiwan University Hospital in 2011 with a BI-RAD of 0 or 4, were interviewed via telephone. The dependent variable was receipt of follow-up or not. The analyses were performed by using χ2 tests and logistic regression models. In total, 528 women were enrolled in the study: 51.2% in BI-RADS 0 group and 56.6% in BI-RADS 4, respectively. In the BI-RADS 0 group, those patients who received a follow-up examination cited the most likely causes to be physician suggestion, health implications, and concerns regarding breast cancer. Patients who did not receive a follow-up examination cited a lack of time and a perception of good personal health as primary reasons. In the BI-RADS 4 group, those patients who received a follow-up examination cited the physician's recommendation and a recognition of the importance of follow-up examinations. Patients who did not receive a follow-up examination cited having received follow-up at another hospital and a desire for a second opinion. In the BI-RADS 0 group, multivariate analysis showed that patients with higher scores in the “perceived benefits” domain were statistically more likely to receive a follow-up examination. There was no significant difference in perceived threats, perceived barriers, action cues, or self-efficacy between

  16. Engaging diverse underserved communities to bridge the mammography divide

    PubMed Central

    2011-01-01

    Background Breast cancer screening continues to be underutilized by the population in general, but is particularly underutilized by traditionally underserved minority populations. Two of the most at risk female minority groups are American Indians/Alaska Natives (AI/AN) and Latinas. American Indian women have the poorest recorded 5-year cancer survival rates of any ethnic group while breast cancer is the number one cause of cancer mortality among Latina women. Breast cancer screening rates for both minority groups are near or at the lowest among all racial/ethnic groups. As with other health screening behaviors, women may intend to get a mammogram but their intentions may not result in initiation or follow through of the examination process. An accumulating body of research, however, demonstrates the efficacy of developing 'implementation intentions' that define when, where, and how a specific behavior will be performed. The formulation of intended steps in addition to addressing potential barriers to test completion can increase a person's self-efficacy, operationalize and strengthen their intention to act, and close gaps between behavioral intention and completion. To date, an evaluation of the formulation of implementation intentions for breast cancer screening has not been conducted with minority populations. Methods/Design In the proposed program, community health workers will meet with rural-dwelling Latina and American Indian women one-on-one to educate them about breast cancer and screening and guide them through a computerized and culturally tailored "implementation intentions" program, called Healthy Living Kansas - Breast Health, to promote breast cancer screening utilization. We will target Latina and AI/AN women from two distinct rural Kansas communities. Women attending community events will be invited by CHWs to participate and be randomized to either a mammography "implementation intentions" (MI2) intervention or a comparison general breast cancer

  17. Digital Libraries.

    ERIC Educational Resources Information Center

    Fox, Edward A.; Urs, Shalini R.

    2002-01-01

    Provides an overview of digital libraries research, practice, and literature. Highlights include new technologies; redefining roles; historical background; trends; creating digital content, including conversion; metadata; organizing digital resources; services; access; information retrieval; searching; natural language processing; visualization;…

  18. [Usefulness and risks of routine mammography for the detection of breast cancer].

    PubMed

    Hernández-Valencia, Marcelino; Hernández-Quijano, Tomás; Zárate, Arturo; Saucedo, Renata

    2014-01-01

    It has been accepted that preclinicall detection of breast cancer by means of the routine practice of mammography could discover the disease at its initial stage; therefore, practicing a mammography annually became widespread as a preventive health measure to diagnose the disease and prevent death due to breast cancer. Over time, the benefit of detection tests has been questioned and demonstration of their benefit, as well as that of the undesirable effects they might cause, has been demanded. There is recent information with regard to an absence of difference in terms of breast cancer mortality as final index between women with or without routine mammography. Additionally, a 20 % frequency has been observed in false-positive diagnoses, with high numbers of women undergoing unnecessary diagnostic procedures due to suspicion