Mammography System Research Articles

The relationship between age of digital mammography systems and number of reported faults and downtime

PurposeTo investigate the relationship between age of mammographic x-ray equipment, and number of reported faults and related consequences. MethodsA centralised online fault reporting database is used by all UK breast screening programmes to collate faults with mammography equipment. Data on faults occurring in 2018 and 2019 for digital x-ray imaging systems were analysed. The effect of the age of mammography systems on the number of equipment faults, and the consequences of these faults was examined. The number of days downtime, number of cancelled appointments, number of repeated images, and number of recalled participants were used to quantify the severity of faults. ResultsThis analysis covers a two year period and includes 4271 faults and 522 individual x-ray sets. On average, an x-ray set was 6.1 years old at the time when a fault occurred. 77% of x-ray sets experienced five of fewer annual faults. X-ray sets of nine years old had the highest average number of annual faults. Systems of ten years old had the highest average number of days downtime per year, and the highest average number of cancellations per year. The indicated primary use of 48% of the x-ray sets included in this analysis was screening, but a disproportionate 87% of cancelled appointments occurred due to faults on these units compared to those used primarily for assessment, or for a mixture of assessment and screening. ConclusionsInformation from this unique dataset can be used to support guidance on equipment replacement programmes for mammographic x-ray sets.

On the suitability of XR-SP2 gafchromic films for dosimetry in mammography

XR-SP2 GafChromic films are extensively used in industrial applications. Even if their sensitivity range overlaps with exposure ranges adopted in x-ray medical imaging, there are only few literature examples of their use in medical physics experiments. This work aims at evaluating the XR-SP2 GafChromic film suitability for dosimetric evaluations on 2D mammography systems as well as at providing a complete picture about this film model. The dose-response curve of the film was evaluated using a Hologic Selenia Dimension scanner for W/Rh spectra at 26 kV (air kerma range: 1.40–10.29 mGy) and at 31 kV (air kerma range: 2.15–15.85 mGy). The suitability of linear and non-linear model was evaluated also in comparison to XR-QA2 GafChromic films, adopted as reference. The uncertainty of air kerma measurements with XR-SP2 films decreased as the air kerma increased, down to 4% at 26 kV and down to 5% at 31 kV, evaluated at the upper boundary of the explored exposure range and for non-linear curve fit. In the case of XR-QA2 films, this value tended to 4% both at 26 kV and at 31 kV. Linear model resulted adequate to describe the dose-response curves of the two GafChromic film types, in particular for reduced exposure ranges (air kerma range: 2.60–10.29 mGy @26 kV; 3.98–15.85 mGy @31 kV); the uncertainty analysis did not outline any difference between linear and non-linear curve fit model. From visual assessment, XR-SP2 film lot was observed to present dark dots on the surface that could affect kerma distribution assessments.

Accuracy of Digital Mammography Unit in Diagnosis Breast Cancer in Gaza Strip, Palestine

Background: Breast cancer is considered a major health problem and the most common cancer among females in both developed and non-developed countries. Early diagnosis of breast cancer decreases morbidities and mortalities. This study attempts to explore the accuracy measures of a digital mammography unit in the diagnosis of breast cancer and compare the mammography results with the final histopathology results. Methods: The study was designed as a cross-sectional prospective hospital base in which mammography examination was used for patients. Then, U/S was performed as a complementary study. All the mammography and U/S reports were reviewed and compared with the histopathology results. Six indicators were used to measure the accuracy of the mammography system using their formulas. SPSS program was used to examine the correlation between imaging results and histopathological findings and to draw the area under the receiver operating characteristic curve (AUC). Confidence interval was considered at 95% and margin of error at 5%. Results: Sensitivity, Specificity, PPV, NPV, accuracy and the area under the ROC curve of mammography alone were 94.9%, 66.7%, 90%, 66.7%, 0.771 and increased to 100%, 76.9%, 90.3%, 100%, 92.7%, 0.917, respectively when Ultrasound was used as a complementary to mammography. A statistically significant moderate correlation was shown between the results of mammography alone and histopathology results (Spearman correlation= 0.527, P-value<0.01), and a statistically significant strong correlation between mammography combined with ultrasound, and histopathology results (Spearman correlation=0.882, P-value<0.01). Conclusion: Mammography is an important tool to detect breast cancer. Mammography when combined with Ultrasound yields a very significant improvement in sensitivity and specificity for diagnosing different breast lesions.

Breast Radiation Exposure of 3D Digital Breast Tomosynthesis Compared to Full-Field Digital Mammography in a Clinical Follow-Up Setting.

According to a position paper of the European Commission Initiative on Breast Cancer (ECIBC), DBT is close to being introduced in European breast cancer screening programmes. Our study aimed to examine radiation dose delivered by digital breast tomosynthesis (DBT) and digital mammography (FFDM) in comparison to sole FFDM in a clinical follow-up setting and in an identical patient cohort. Retrospectively, 768 breast examinations of 96 patients were included. Patients received both DBT and FFDM between May 2015 and July 2019: (I) FFDM in cranio-caudal (CC) and DBT in mediolateral oblique (MLO) view, as well as a (II) follow-up examination with FFDM in CC and MLO view. The mean glandular dose (MGD) was determined by the mammography system according to Dance’s model. The MGD (standard deviation (SD), interquartile range (IQR)) was distributed as follows: (I) (CCFFDM+MLODBT) (a) left FFDMCC 1.40 mGy (0.36 mGy, 1.13–1.59 mGy), left DBTMLO 1.62 mGy (0.51 mGy, 1.27–1.82 mGy); (b) right FFDMCC 1.36 mGy (0.34 mGy, 1.14–1.51 mGy), right DBTMLO 1.59 mGy (0.52 mGy, 1.27–1.62 mGy). (II) (CCFFDM+MLOFFDM) (a) left FFDMCC 1.35 mGy (0.35 mGy, 1.10–1.60 mGy), left FFDMMLO 1.40 mGy (0.39 mGy, 1.12–1.59 mGy), (b) right FFDMCC 1.35 mGy (0.33 mGy, 1.12–1.48 mGy), right FFDMMLO 1.40 mGy (0.36 mGy, 1.14–1.58 mGy). MGD was significantly higher for DBT mlo views compared to FFDM (p < 0.001). Radiation dose was significantly higher for DBT in MLO views compared to FFDM. However, the MGD of DBT MLO lies below the national diagnostic reference level of 2 mGy for an FFDM view. Hence, our results support the use of either DBT or FFDM as suggested in the ECIBC’s Guidelines.

A statistical alternative to current measures of image quality in digital mammography

Objective. Mammogram image quality in European breast screening systems is defined by threshold gold thickness (T) assessment of the CDMAM contrast-detail phantom. Previous studies have outlined several limitations of the phantom including expense, number of images required and inter-phantom manufacturing variability. Two alternative approaches to image quality assessment for routine quality control are examined and compared to the CDMAM technique: (i) A detectability index (d′) based on a non-prewhitened model observer with an eye filter (NPWE) and (ii) A statistical estimate of contrast based on image noise levels (CSTAT ). Approach. The d′ calculation follows a previously published methodology based on the NNPS and contrast, both measured from an image of 5 cm of PMMA containing a 0.2 mm Al target, as well as the MTF measured under standard conditions. For the proposed statistical method, pixels in the centre of the same NNPS image were re-binned into a range of equivalent CDMAM target areas. For any area, the minimum contrast necessary to distinguish a signal from the background, CSTAT , is 3.29σ at a 95% level of confidence, where σ is the standard deviation of the background pixels. Theoretical analysis predicts a simple relationships between CSTAT , T and d′. Measured values of CSTAT were compared to T and d′ as a function of air kerma at the detector for ten digital mammography systems from three different manufacturers. Main Results. Theoretical relationships between CSTAT , d′ and T were demonstrated. Minimum acceptable image quality performance for 0.10 and 0.25 mm diameter discs, defined by the European Guidelines in terms of T, are equivalent to d′ values of 0.85 and 5.36 and threshold CSTAT values of 0.055 and 0.022. Significance. Strong correlations between log(T), log(d′) and log(CSTAT ) suggest that either alternative approach produces information corresponding to that obtained using the CDMAM. CSTAT should be considered as a simple, objective and cost-effective alternative to routine image quality assessment in mammography.

Spectra for little unusual anode/filter combinations, in the metrological and simulated cases / Espectros para pequenas combinações anódico/filtro incomuns, nos casos metrológicos e simulados

It is necessary to evaluate the spectra with an up-to-date solid-state detector in a mammographic system, utilizing exotic anode/filter combinations and PMMA phantoms from different thicknesses. It has seen that today dual energy mammography and tomosynthesis applications are using tungsten anode spectra up to 49 kV with exotic filters, such as silver (Ag), palladium (Pd), molybdenum (for the W/Mo combination), and so on. Based on this, this work was made an experiment in the metrological and simulated case. It was used a spectrometer with the W/Pd and W/Mo anode/filters, in some tube voltages with PMMA slabs, to find the respective spectra. The same situations were made for the simulations in the Monte Carlo, in the simulate case. Considering the uncertainty of the measurements, the spectra obtained are in agreement with the references provided by the equipment and with internationally adopted standards. Through, results obtained both in metrological and simulated cases can be validated for future uses in the mammography.

An Analysis Scheme for 3D Visualization of Positron Emitting Radioisotopes Using Positron Emission Mammography System

Proton range monitoring and verification is important to enhance the effectiveness of treatment by ensuring that the correct dose is delivered to the correct location. Upon proton irradiation, different positron emitting radioisotopes are produced by the inelastic nuclear interactions of protons with the target elements. Recently, it was reported that the 16O(p,2p2n)13N reaction has a relatively low threshold energy, and it could be potentially used for proton range verification. In the present work, we have proposed an analysis scheme (i.e., algorithm) for the extraction and three-dimensional visualization of positron emitting radioisotopes. The proposed step-by-step analysis scheme was tested using our own experimentally obtained dynamic data from a positron emission mammography (PEM) system (our developed PEMGRAPH system). The experimental irradiation was performed using an azimuthally varying field (AVF) cyclotron with a 80 MeV monoenergetic pencil-like beam. The 3D visualization showed promising results for proton-induced radioisotope distribution. The proposed scheme and developed tools would be useful for the extraction and 3D visualization of positron emitting radioisotopes and in turn for proton range monitoring and verification.

Evaluation of the Accuracy of the Displayed Average Glandular Dose in Mammography

We aimed to clarify the error of displayed value against the measured value of the average glandular dose (AGD) in two-dimensional (2D) mammography and digital breast tomosynthesis (DBT) and evaluate the accuracy of the displayed AGD as an index to estimate AGD. Polymethyl methacrylate (PMMA) phantoms with thicknesses varying from 20 to 80 mm were imaged, and the values displayed on the mammography system were used as the displayed AGD. The incident air kerma and the half-valued layer were measured, and the measured AGD in 2D mammography was calculated using the equation by Dance et al. On the other hand, the measured AGD in DBT was calculated by correcting for different projection angles. The relative error to the PMMA thickness was evaluated by assessing the relative error of the displayed AGD against the measured AGD. The maximum relative error of the displayed AGD against the measured AGD was 17.3% in 2D mammography, 19.1% in the standard (ST) mode, and 19.8% in the high-resolution (HR) mode. The relative error of the displayed AGD against the measured AGD tended to increase with increase in PMMA thickness. This tendency was especially noticeable for PMMA with thicknesses of 70 and 80 mm in DBT.

Socio-demographic determinants of mammography uptake among women of 40 years and above in Calabar, South-South, Nigeria: a cross-sectional study.

mammography has the potential for identifying high risk women with breast cancer. Early detection is important in reducing mortality and morbidity, and crucial for better prognosis. Mammography is poorly practiced in Nigeria. This study assessed the association between socio-demographic characteristics and uptake of mammography among women ≥40 years. a cross-sectional descriptive study design was employed and data was collected from 365 consenting participants in Calabar, Nigeria, using pre-tested questionnaire. SPSS Version 20 was used for data entry and analysis. The results were descriptively presented by frequencies and percentages. Pearson Chi-Square (χ2) analysis was performed to detect the association between variables at 5% level of significance (p-value of ≤0.05). only 9.9% of participants had a mammography, majority 90.1% never had. Uptake was highest among respondents with tertiary education, married, Civil/Public Servants, and those in the high income level categorization. Educational status, marital status, occupation and age were not statistically significantly associated with mammography uptake (p>0.05). Only religious denominational affiliation (p = 0.02) and income level (p = 0.002) were statistically significantly associated with uptake. Barriers to uptake were poor knowledge about mammography (49.8%), psychosocial (37.8%), economic (17.1%) and health systems (11.5%). Key facilitators to uptake were encouragement/counselling by health workers (44.0%) and presence of breast problems (37.4%). mammography uptake in Calabar, Nigeria was extremely low. Therefore, regular awareness campaigns targeting women at faith-based settings, and provision of mammography screening services at subsidized rates will enhance knowledge level and uptake of mammography.

PERFORMANCE COMPARISON OF SYSTEMS WITH FULL-FIELD DIGITAL MAMMOGRAPHY, DIGITAL BREAST TOMOSYNTHESIS AND CONTRAST-ENHANCED SPECTRAL MAMMOGRAPHY.

The purpose is to compare full-field digital mammography (FFDM), digital breast tomosynthesis (DBT) and contrast-enhanced spectral mammography (CESM) technologies on three mammography systems in terms of image quality and patient dose. Two Senographe Essential with DBT and CESM (denoted S1 and S2) and one Selenia Dimensions (S3) with FFDM and DBT were considered. Dosimetry methods recommended in the European protocol were used. Image quality was tested with CDMAM in FFDM and DBT and with ideal observer method in FFDM. Mean values of mean glandular dose (MGD) from whole patient samples on S1, S2 and S3 were as follows: FFDM 1.65, 1.84 and 2.23mGy; DBT 2.03, 1.96 and 2.87mGy; CESM 2.65 and 3.16mGy, respectively. S3 exhibited better low-contrast detectability for the smallest sized discs of CDMAM and ideal observer in FFDM, and for the largest sized discs in DBT, at similar dose levels.

The value of computer aided detection system FOR mammography in the breast cancer screening: single-center, prospective, randomized clinical trial

Purpose. To assess the influence of mammography mapping with the help of computer-aided detection system (CAD) MammCheck II of our own design on the relapse-free survival (RFS) in breast cancer (BC) patients detected during the combined (mammographic and ultrasound [US]) screening. Materials and methods. 10732 women aged 40-87 years old (mean age: 52.20±8.63) who performed mammography were randomized to the standard screening group (mammography → US of the dense breasts) or to the group of CAD-assisted screening (mammography → CAD → targeted US of suspicious CAD markings, as well as the standard US of the dense breasts; CAD group). The primary endpoint was the 3-years RFS. Results. Totally, in the standard screening group we identified 230 BCs (4.29%), in the CAD group — 248 BCs (4.62%; p&gt;0.05), including 49 (21.20%) и 88 (35.48%) 0-I stage BCs, respectively (p&lt;0.05). Median of the primary tumor size was significantly lower in the CAD group (18 mm) compared to the standard screening group (25 mm; р&lt;0.05). 3-years RFS was significantly higher (87.90%) in the CAD group compared to the standard screening group (81.20%; р&lt;0.05). Conclusion. Breast US after the previous mammography CAD mapping significantly increases the 3-years RFS of women with combined screening-detected BC.

Overhaul of Radiological Mammography Check-ups for Early Malignancy Diagnosis during COVID-19 Pandemic

Background. The article reports the number of examinations with stationary mammography systems, in outpatient screenings, as well as in a mobile mammography survey across the Sverdlovsk Region.Aim. A study of expedience and design of radiological breast check-ups (exemplified by mammography) for early cancer diagnosis under the COVID-19 pandemic situation.Materials and methods. A survey based at the Sverdlovsk Regional Oncology Dispensary’s Department of Diagnostic Radiology analysed the expedience and design of non-invasive diagnostic procedures in a case study of breast X-ray checkups (mammography) in the Sverdlovsk Region during 2019—2020. Th e survey used the Sverdlovsk Region population statistics on breast malignancy incidence for 2019—2020.Results. According to reports, the number of outpatient screening surveys significantly decreased in 2020 vs. 2019 due to the coronavirus pandemic and effective ban on screenings and medical check-ups. Th e mobile mammography screening numbers increased more than twice in 2020 vs. 2019.Discussion. Screening measures continued during the COVID-19 pandemic. Clinicians adhered to local guidelines, while fully complying with the recommendations to contain SARS-CoV-2 infection. Th e growth of mobile mammography screenings enabled completion of the annual check-up plan, however, the breast malignancy detection rate slightly dropped in 2020 compared to 2019.Conclusion. Mammography screenings at the Sverdlovsk Regional Oncology Dispensary in 2019--2020 demonstrate the expedience and good organisation of breast radiological check-ups (mammography) in Sverdlovsk Region. Accounting for the epidemiological state of coronavirus infection, a positive trend is evident towards growing examinations and improved breast malignancy detection, which lowers mortality accordingly among the female population of Sverdlovsk Region.

The value of computer aided detection system for mammography in the fatty breast: the results of the single-centered, prospective, randomized clinical trial

Aim. To assess the reasonability to use CAD added to mammography with subsequent targeted ultrasound (US) of CAD markings in patients with low-density (ACR A-В) breasts.Materials and methods. In the prospective study we included 2326 women with low breast density. They were randomized for CAD (MammCheck II of our own design) checking with subsequent targeted US (MMG + CAD group) or without CAD (MMG only group). After the initial screening we performed the 3-year follow-up phase.Results. Totally, during the primary screening in the MMG only group we found 77 breast cancers (BCs) (28,57% of them sized less than 1 cm), in the MMG + CAD group – 69 BCs (36,23% of them sized less than 1 cm), р &gt; 0.05. The suspicious lesion was identified only during the targeted US of the CAD marking in 4 of 25 women in the MMG + CAD group, and all these BCs were below 1 cm in size. During the subsequent follow-up in the MMG only group we found 5 additional BCs, with no such cases in the MMG + CAD group (p &lt; 0.05). Three of these five BCs were retrospectively marked by CAD. The only visible BC that was not marked by CAD was 3 mm in size.Discussion. The overall false positive marking rate was 0.31 и 0.28 per film-screen and digital image, respectively (р &gt; 0.05).Conclusion. The CAD usage added to mammography with subsequent targeted US of markings in patients with low-density (ACR A-В) breast is reasonable due to the significant decrease of the BC rate diagnosed during the 3-year follow-up. This combination detected 77 of the 77 (100.00%) BCs compared to 69 of 74 (93.24%) BCs when only mammography used.

Dual-energy tissue cancellation in mammography for improved detection of microcalcifications and neoplasms: A phantom study

Dual-energy mammography and the tissue-cancellation algorithm were applied to the problem of enhancing the detectability of calcifications and lesions in cluttered mammogram background. A multicomponent (plexiglass (PMMA), polypropylene (PP), water) tissue-equivalent breast phantom and a standard full-field digital mammography system operating in two of its standard operating modes (26 kVp, 40 mAs, Mo/Mo and 49 kVp, 6.3 mAs, Rh/Rh target/filter) were used. We studied to what extent the contrast between the tissue substitutes can be eliminated depending on the difference in their attenuation properties, and whether the obtained level of contrast cancellation is sufficient to unambiguously discriminate microcalcifications and inserts from the background.Mixed results were obtained. It was shown that the tissue-cancellation method can provide nearly perfect elimination of the background clutter (17-fold decrease in standard deviation) for homogeneous materials with close attenuation properties (PMMA and water) while increasing the contrast of a third material (PP, 1.7 times increase in contrast-to-noise ratio), thus facilitating its detection and delineation.However, canceling the contrast between materials with more different attenuation properties (PP and water) does not simultaneously lead to any significant enhancement of the contrast of a third material (PMMA), if its attenuation properties are close to those of either PP or water. Moreover, intrinsic inhomogeneity of the phantom constituents becomes important as it results in incomplete contrast cancellation and preservation of visually significant background clutter. Although contrast cancellation increased the signal-to-noise ratio of microcalcifications by about 33%, the relative contrast calcifications—background​ can diminish, making it possible for the remaining clutter to obscure the microcalcifications.

OD123 - Small-size details detection performance of digital breast tomosynthesis, synthetic 2D and conventional full-field digital mammography images for different mammography systems: a multicenter study

OD123 - Small-size details detection performance of digital breast tomosynthesis, synthetic 2D and conventional full-field digital mammography images for different mammography systems: a multicenter study

P168 - Evaluation of the CDMAM phantom in the determination of the contrast-detail threshold thickness in a digital mammography system

P168 - Evaluation of the CDMAM phantom in the determination of the contrast-detail threshold thickness in a digital mammography system

OD89 - Performance comparison of mammography systems with FFDM, DBT and CESM: a dosimetry study

OD89 - Performance comparison of mammography systems with FFDM, DBT and CESM: a dosimetry study

P147 - Performance comparison of mammography systems with FFDM and DBT: an image quality study

P147 - Performance comparison of mammography systems with FFDM and DBT: an image quality study

The IAEA remote and automated quality control methodology for radiography and mammography.

Radiography remains the most widely used imaging modality throughout the world. Additionally, while it has been demonstrated that a quality control (QC) program, especially in mammography, improves image quality, weekly technologist QC testing might be lacking even where there is clinical qualified medical physicist (CQMP) support. Therefore, the International Atomic Energy Agency (IAEA) developed simple QC phantoms that can easily be used on a regular basis (daily/weekly) for radiography and mammography. These are simple in design and use materials that are easily accessible in most parts of the world. A software application is also developed that automatically analyzes images and Digital Imaging and Communications in Medicine (DICOM) header information. It exports data to a comma‐separated values (CSV) file that is read by a Microsoft Excel® spreadsheet for documentation and graphical analysis. The phantom and the software were tested in four institutions (in Costa Rica and the United States of America) both on computed radiography and direct digital mammography and radiography systems. Data were collected over a 3‐year period. No corrective actions were taken on the data, but service was performed on two of the units. Results demonstrated noise that could be attributed to suboptimal placement of the phantom and incorrect data being put into the DICOM header. Preliminary evaluation of the IAEA methodology has demonstrated that it can provide meaningful QC data that are sensitive to changes in the imaging systems. Care must be taken at implementation to properly train personnel and ensure that the image data, including the DICOM header, are being correctly transmitted. The methodology gives the opportunity for a single CQMP to provide QC services even to remote sites where travel is prohibitive, and it is feasible and easy to implement.

Effect of Compression Force and Target or Target/Filter Combination on Mean Glandular Dose for Japanese Women in Full-Field Digital Mammography System

We constructed a mammography database of 807 Japanese women and 2,772 images obtained using five commercial full-field digital mammography (FFDM) devices at four different facilities. Five types of mammography devices fabricated by four manufacturers were used: one with a Mo target (AMULET F), one with Mo and Rh targets (Senographe DS), one with Mo and W targets (AMULET), and two with a W target (MAMMOMAT Fusion and Selenia Dimensions). The purpose of this study was to focus on the mean glandular dose (MGD) in the database and analyze the difference in the MGD of Japanese women radiographed by mammographic devices with different targets or target/filter combinations. Furthermore, we clarify the difference between the displayed and measured MGDs for the three types of mammography devices. The average compression pressure and compression breast thickness of the Japanese women in the mammography in this study were 90.9±21.7 N and 43.3±12.9 mm, respectively. The breast compression pressure slightly varied depending on the facility or FFDM device, while the compression breast thickness decreased with the increase in the compression pressure for all FFDM devices. Differences in breast compression thickness existed depending on the mammography devices. The MGDs of the two types of mammography devices using the W target were smallest (1.335±0.358, 1.218±0.464 mGy). The displayed and measured MGDs of the three types of FFDM devices had a good correlation. However, the difference between the displayed and measured MGDs of the two devices increased with the MGD.