Mammography is a very well-established imaging modality for the early detection and diagnosis of breast cancer. However, since the introduction of digital imaging to the realm of radiology, more ...advanced, and especially tomographic imaging methods have been made possible. One of these methods, breast tomosynthesis, has finally been introduced to the clinic for routine everyday use, with potential to in the future replace mammography for screening for breast cancer. In this two part paper, the extensive research performed during the development of breast tomosynthesis is reviewed, with a focus on the research addressing the medical physics aspects of this imaging modality. This first paper will review the research performed on the issues relevant to the image acquisition process, including system design, optimization of geometry and technique, x-ray scatter, and radiation dose. The companion to this paper will review all other aspects of breast tomosynthesis imaging, including the reconstruction process.
From mammogram results to the O. J. Simpson trial and null hypothesis significance testing – William P. Skorupski and Howard Wainer demonstrate a straightforward method for avoiding errors in ...statistical reasoning
William P. Skorupski and Howard Wainer demonstrate a straightforward method for avoiding errors in statistical reasoning
Purpose:
The purpose of this study is to quantify the differences in detectability between full field digital mammography (FFDM), digital breast tomosynthesis (DBT), and synthetic mammography (SM) ...for challenging, low contrast signals, in the context of both a uniform and an anthropomorphic, textured phantom.
Methods:
Images of the phantoms were acquired using a Hologic Selenia Dimensions system. Images were taken at 50%, 100%, and 200% of the dose delivered under automatic exposure control (AEC). Low-contrast disks, created using an inkjet printer with iodine-doped ink, were inserted into the phantom. The disks varied in diameter from 210 to 630 μm, and in local contrast from 1.1% to 2.8% in regular increments. Human observers located the disks in a 4 alternative forced choice experiment. Proportion correct (PC) was computed as the number of correct localizations out of the total number of tries.
Results:
Overall, scores from FFDM and DBT were consistently greater than scores from SM. At an exposure corresponding to the AEC setting, mean PC scores for the largest disks with the uniform phantom were 0.80 for FFDM, 0.83 for DBT, and 0.66 for SM, with the same rank ordering at other doses. Scores were similar but lower for the nonuniform background. At an exposure twice the AEC setting, however, the difference between uniform and nonuniform scores was most pronounced for DBT alone. Differences between scores for FFDM and SM were statistically significant, while those between FFDM and DBT were not. Scores were used to compute the minimum contrast level needed to reach 62.5% detection rate. The minimum contrast for SM was 36%–81% higher compared to FFDM or DBT, in either background.
Conclusions:
This study shows that an anthropomorphic phantom and lesions inserts may be used to conduct a reader study. Detectability was significantly lower for synthetic mammography than for FFDM or DBT, for all conditions. Additionally, observer performance was consistently lower for the anthropomorphic phantom, indicating the greater challenge due to anatomical background. Because of this, it may be important to use realistic phantoms in observer studies in order to draw conclusions that are more clinically relevant.
Improvising and developing state of the art techniques for breast cancer detection have always been an area of great interest in the field of imaging. Adding intravenous contrast to any imaging ...study, is well-known to increase the sensitivity and specificity of detection of a pathological process, especially in the setting of neoplasia secondary to tumor neoangiogenesis. Contrast enhanced MRI is known to be highly sensitive breast cancer screening tool till date, however, has been limited by long scan times, claustrophobia experienced by some women and high false positive findings. Despite continued advances in digital mammography technique, significant limitations have always been experienced in detection of small cancers especially in the setting of dense breast parenchyma. Implementing dual energy subtraction technique to digital mammography, made contrast enhanced mammography a viable technique to improve cancer detection. We aim to discuss the status of contrast enhanced mammography in this brief communication, emphasizing technical background, image acquisition, clinical applications, and future directions.
•Contrast enhanced mammography is one of the latest imaging techniques garnering attention in the field of breast imaging.•Breast cancer remains a major public health issue for women worldwide.•Contrast enhanced mammography is superior to routine mammography in the setting of dense breast parenchyma.•Contrast enhanced mammography is readily available and remains an effective adjunct to routine mammography in detection of occult malignancy.
Update of the 2002 U.S. Preventive Services Task Force (USPSTF) recommendation statement on screening for breast cancer in the general population.
The USPSTF examined the evidence on the efficacy of ...5 screening modalities in reducing mortality from breast cancer: film mammography, clinical breast examination, breast self-examination, digital mammography, and magnetic resonance imaging in order to update the 2002 recommendation. To accomplish this update, the USPSTF commissioned 2 studies: 1) a targeted systematic evidence review of 6 selected questions relating to benefits and harms of screening, and 2) a decision analysis that used population modeling techniques to compare the expected health outcomes and resource requirements of starting and ending mammography screening at different ages and using annual versus biennial screening intervals.
The USPSTF recommends against routine screening mammography in women aged 40 to 49 years. The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take into account patient context, including the patient's values regarding specific benefits and harms. (Grade C recommendation) The USPSTF recommends biennial screening mammography for women between the ages of 50 and 74 years. (Grade B recommendation) The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of screening mammography in women 75 years or older. (I statement) The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of clinical breast examination beyond screening mammography in women 40 years or older. (I statement) The USPSTF recommends against clinicians teaching women how to perform breast self-examination. (Grade D recommendation) The USPSTF concludes that the current evidence is insufficient to assess additional benefits and harms of either digital mammography or magnetic resonance imaging instead of film mammography as screening modalities for breast cancer. (I statement).
This systematic review is an update of evidence since the 2002 U.S. Preventive Services Task Force recommendation on breast cancer screening.
To determine the effectiveness of mammography screening ...in decreasing breast cancer mortality among average-risk women aged 40 to 49 years and 70 years or older, the effectiveness of clinical breast examination and breast self-examination, and the harms of screening.
Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews (through the fourth quarter of 2008), MEDLINE (January 2001 to December 2008), reference lists, and Web of Science searches for published studies and Breast Cancer Surveillance Consortium for screening mammography data.
Randomized, controlled trials with breast cancer mortality outcomes for screening effectiveness, and studies of various designs and multiple data sources for harms.
Relevant data were abstracted, and study quality was rated by using established criteria.
Mammography screening reduces breast cancer mortality by 15% for women aged 39 to 49 years (relative risk, 0.85 95% credible interval, 0.75 to 0.96; 8 trials). Data are lacking for women aged 70 years or older. Radiation exposure from mammography is low. Patient adverse experiences are common and transient and do not affect screening practices. Estimates of overdiagnosis vary from 1% to 10%. Younger women have more false-positive mammography results and additional imaging but fewer biopsies than older women. Trials of clinical breast examination are ongoing; trials for breast self-examination showed no reductions in mortality but increases in benign biopsy results.
Studies of older women, digital mammography, and magnetic resonance imaging are lacking.
Mammography screening reduces breast cancer mortality for women aged 39 to 69 years; data are insufficient for older women. False-positive mammography results and additional imaging are common. No benefit has been shown for clinical breast examination or breast self-examination.
Purpose:
The purpose of this work is to investigate the feasibility of grating‐based, differential phase‐contrast, full‐field digital mammography (FFDM) in terms of the requirements for field‐of‐view ...(FOV), mechanical stability, and scan time.
Methods:
A rigid, actuator‐free Talbot interferometric unit was designed and integrated into a state‐of‐the‐art x‐ray slit‐scanning mammography system, namely, the Philips MicroDose L30 FFDM system. A dedicated phase‐acquisition and phase retrieval method was developed and implemented that exploits the redundancy of the data acquisition inherent to the slit‐scanning approach to image generation of the system. No modifications to the scan arm motion control were implemented.
Results:
The authors achieve a FOV of 160 × 196 mm consisting of two disjoint areas measuring 77 × 196 mm with a gap of 6 mm between them. Typical scanning times vary between 10 and 15 s and dose levels are lower than typical FFDM doses for conventional scans with identical acquisition parameters due to the presence of the source‐grating G0. Only minor to moderate artifacts are observed in the three reconstructed images, indicating that mechanical vibrations induced by other system components do not prevent the use of the platform for phase contrast imaging.
Conclusions:
To the best of our knowledge, this is the first attempt to integrate x‐ray gratings hardware into a clinical mammography unit. The results demonstrate that a scanning differential phase contrast FFDM system that meets the requirements of FOV, stability, scan time, and dose can be build.
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