The impact of simulated motion blur on lesion detection performance in full field digital mammography

Objective: Motion blur is a known phenomenon in full-field digital mammography, but the impact on lesion detection is unknown. This is the first study to investigate detection performance with varying magnitudes of simulated motion blur. Method: Seven observers (15±5 years’ reporting experience) evaluated 248 cases (62 containing malignant masses, 62 containing malignant microcalcifications and 124 normal cases) for three conditions: no blurring (0 mm) and two magnitudes of simulated blurring (0.7 mm and 1.5 mm). Abnormal cases were biopsy proven. Mathematical simulation was used to provide a pixel shift in order to simulate motion blur. A free-response observer study was conducted to compare lesion detection performance for the three conditions. The equally weighted jackknife alternative free-response receiver operating characteristic (wJAFROC) was used as the figure of merit. Test alpha was set at 0.05 to control probability of Type I error. Results: wJAFROC analysis found a statistically significant difference in lesion detection performance for both masses (F(2,22) = 6.01, P=0.0084) and microcalcifications (F(2,49) = 23.14, P<0.0001). The figures of merit reduced as the magnitude of simulated blurring increased. Statistical differences were found between some of the pairs investigated for the detection of masses (0.0mm v 0.7mm, and 0.0mm v 1.5mm) and all pairs for microcalcifications (0.0 mm v 0.7 mm, 0.0 mm v 1.5 mm, and 0.7 mm v 1.5 mm). No difference was detected between 0.7 mm and 1.5 mm for masses. Conclusion: Mathematical simulation of motion blur caused a statistically significant reduction in lesion detection performance. These false negative decisions could have implications for clinical practice. Advances in knowledge: This research demonstrates for the first time that motion blur has a negative and statistically significant impact on lesion detection performance digital mammography

The influence of season, photoperiod, and pineal melatonin on immune function.

In addition to the well-documented seasonal cycles of mating and birth, there are also significant seasonal cycles of illness and death among many animal populations. Challenging winter conditions (i.e., low ambient temperature and decreased food availability) can directly induce death via hypothermia, starvation, or shock. Coping with these challenges can also indirectly increase morbidity and mortality by increasing glucocorticoid secretion, which can compromise immune function. Many environmental challenges are recurrent and thus predictable; animals could enhance survival, and presumably increase fitness, if they could anticipate immunologically challenging conditions in order to cope with these seasonal threats to health. The annual cycle of changing photoperiod provides an accurate indicator of time of year and thus allows immunological adjustments prior to the deterioration of conditions. Pineal melatonin codes day length information. Short day lengths enhance several aspects of immune function in laboratory studies, and melatonin appears to mediate many of the enhanced immunological effects of photoperiod. Generally, field studies report compromised immune function during the short days of autumn and winter. The conflict between laboratory and field data is addressed with a multifactor approach. The evidence for seasonal fluctuations in lymphatic tissue size and structure, as well as immune function and disease processes, is reviewed. The role of pineal melatonin and the hormones regulated by melatonin is discussed from an evolutionary and adaptive functional perspective. Finally, the clinically significance of seasonal fluctuations in immune function is presented. Taken together, it appears that seasonal fluctuations in immune parameters, mediated by melatonin, could have profound effects on the etiology and progression of diseases in humans and nonhuman animals. An adaptive functional perspective is critical to gain insights into the interaction among melatonin, immune function, and disease processes

Consequences of Artificial Light at Night: The Linkage between Chasing Darkness Away and Epigenetic Modifications

Epigenetics is an important tool for understanding the relation between environmental exposures and cellular functions, including metabolic and proliferative responses. At our research center, we have devolved a mouse model for characterizing the relation between exposure to artificial light at night (ALAN) and both global DNA methylation (GDM) and breast cancer. Generally, the model describes a close association between ALAN and cancer responses. Cancer responses are eminent at all light spectra, with the prevalent manifestation at the shorter end of the visible spectrum. ALAN-induced pineal melatonin suppression is the principal candidate mechanism mediating the environmental exposure at the molecular level by eliciting aberrant GDM modifications. The carcinogenic potential of ALAN can be ameliorated in mice by exogenous melatonin treatment. In contrast to BALB/c mice, humans are diurnal species, and thus, it is of great interest to evaluate the ALAN-melatonin-GDM nexus also in a diurnal mouse model. The fat sand rat (Psammomys obesus) provides an appropriate model as its responses to photoperiod are comparable to humans. Interestingly, melatonin and thyroxin have opposite effects on GDM levels in P. obesus. Melatonin, GDM levels, and even thyroxin may be utilized as novel biomarkers for detection, staging, therapy, and prevention of breast cancer progression

Recall Rates in Screening Mammography: Variability in Performance and Decisions

Having a high recall rate may increase the probability of cancer being detected earlier, however it also has been related to increased false positive decisions, causing significant psychological and economical costs for both screened women and the mammography screening service. Therefore, the purpose of this thesis is to explore the impact of various recall rates on breast radiologists’ performance in a laboratory setting. Methods This study was designed to encompass two aspects 1) the effect of setting varying recall rates on the performance of breast radiologists in screening mammography 2) types of mammographic appearances of breast cancer are more likely to be missed at different recall rates. Five Australian breast radiologists were recruited to read one single test set of 200 mammographic cases (180 normal and 20 abnormal cases) over three different recall rate conditions: free recall, 15% and 10%. These radiologists were tasked with marking the location of suspicious lesions and providing a confidence. Results A significant decrease in radiologists’ performance was observed when reading at lower recall rates, with lower sensitivity (P=0.002), case location sensitivity (P=0.002) and ROC AUC (P=0.003). Reading at a lower recall rate had a significant increase in specificity (P=0.002). The second study of this thesis showed that breast radiologists demonstrated lower sensitivity and receiver ROC AUC for non-specific density (NSD) (P=0.04 and P=0.03 respectively) and mixed features (P=0.01 and P=0.04 respectively) when reading at 15% and 10% recall rates. No significant change was observed on cancer characterized with stellate masses (P=0.18 and P=0.54 respectively) and architectural distortion (P=1.00 and P=0.37 respectively). Conclusion Reducing the number of recalled cases to 10% significantly reduced breast radiologists’ performance. Stellate masses were likely to be recalled (90.0%) while NSDs were likely to be missed (45.6%) at reduced recall rates

Focal Spot, Spring 1973

https://digitalcommons.wustl.edu/focal_spot_archives/1005/thumbnail.jp

Measures to reduce fine dust emission from poultry houses: reduction from broiler houses by ionization

In this study the effect was determined of a commercially available air ionization system on the reduction of airborne dust in a broiler house. Results showed a reduction, based on particle mass, of 36% and 10% for PM10 and PM2.5, respectivel

A systematic review of viewing conditions and monitor specifications in mammography

Objectives The purpose of this systematic review was to establish the current status of recommended monitor specifications and viewing conditions in mammography for image acquisition and reporting rooms. A literature search was completed between August 2018 and March 2019 using ScienceDirect, PubMed, Web of Science and MEDLINE databases. An additional manual search was performed to identify relevant guidelines to support the review. Only articles and guidelines written in English were included. Key findings Results were selected according to the following criteria; articles detailing (i) monitor specification and, (ii) viewing conditions in mammography acquisition and reporting rooms. Twenty-one studies met the inclusion criteria. Six papers described monitor specifications, five described viewing conditions and ten guideline documents were identified from the UK, Europe and the US. Common outcomes were that monitors with 3 or 5 MP resolution seemed to be preferred and at the same time higher illumination levels (>15 lux) were found to decrease the luminance of the monitors and negatively impact the assessment of image quality. Contrary to this, the majority of guideline documents recommended illumination levels above 20 Lux. Finally, there is a lack of guidance for viewing conditions in acquisition rooms. Conclusion This review did not reveal any strong evidence for the proposed room illumination levels in acquisition rooms. In reference to monitors specifications, there is preference for using higher resolution displays (3 and 5 MP) but again, the evidence is not strong. Moreover, variance exists in the guidelines and that promotes inconsistency in mammography departments. Implications for practice This review highlights the lack of standardised guidelines and the need for further research on the viewing conditions and monitor specifications for the acquisition rooms in mammography

Photovoltaic Energy Harvesting for Millimeter-Scale Systems

The Internet of Things (IoT) based on mm-scale sensors is a transformational technology that opens up new capabilities for biomedical devices, surveillance, micro-robots and industrial monitoring. Energy harvesting approaches to power IoT have traditionally included thermal, vibration and radio frequency. However, the achievement of efficient energy scavenging for IoT at the mm-scale or sub mm-scale has been elusive. In this work, I show that photovoltaic (PV) cells at the mm-scale can be an alternative means of wireless power transfer to mm-scale sensors for IoT, utilizing ambient indoor lighting or intentional irradiation of near-infrared (NIR) LED sources through biological tissue. Single silicon and GaAs photovoltaic cells at the mm-scale can achieve a power conversion efficiency of more than 17 % for silicon and 30 % for GaAs under low-flux NIR irradiation at 850 nm through the optimized device structure and sidewall/surface passivation studies, which guarantees perpetual operation of mm-scale sensors. Furthermore, monolithic single-junction GaAs photovoltaic modules offer a means for series-interconnected cells to provide sufficient voltage (> 5 V) for direct battery charging, and bypassing needs for voltage up-conversion circuitry. However, there is a continuing challenge to miniaturize such PV systems down to the sub mm-scale with minimal optical losses from device isolation and metal interconnects and efficient voltage up-conversion. Vertically stacked dual-junction PV cells and modules are demonstrated to increase the output voltage per cell and minimize area losses for direct powering of miniature devices for IoT and bio-implantable applications with low-irradiance narrowband spectral illumination. Dual-junction PV cells at small dimensions (150 µm x 150 µm) demonstrate power conversion efficiency greater than 22 % with more than 1.2 V output voltage under low-flux 850 nm NIR LED illumination, which is sufficient for batteryless operation of miniaturized CMOS IC chips. The output voltage of dual-junction PV modules with eight series-connected single cells is greater than 10 V while maintaining an efficiency of more than 18 %. Finally, I demonstrate monolithic PV/LED modules at the µm-scale for brain-machine interfaces, enabling two-way optical power and data transfer in a through-tissue configuration. The wafer-level assembly plan for the 3D vertical integration of three different systems including GaAs LED/PV modules, CMOS silicon chips, and neural probes is proposed.PHDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/163261/1/esmoon_1.pd

Evaluation of commercially available moisture-sensing devices to monitor feather wetness

The ability to detect moisture in broiler feathers for five moisture-sensing devices using varying techniques, an infrared (IR) camera, and one type of moisture-sensitive paper was evaluated in two experiments; using artificial feather beds in laboratory settings and in field conditions using live birds. In the first experiment (lab testing-phase I), seven levels of moisture were applied once per day to the swatches with four different feather densities to account for moisture variation and feather density present in commercial barn conditions. True moisture of the feathers was determined gravimetrically on a daily basis. Using the five devices, 20 readings each were acquired from each of the swatches. The average temperatures of a selected area from images captured using an IR camera along with average device readings were compared with the true moisture content. Moisture-sensitive paper images were analyzed in Photoshop and Matlab prior to statistical analysis. Data from all devices, the IR camera, and moisture-sensitive paper were analyzed using SAS Procedure GLM to define relationships between the true moisture content and the readings. The devices were analyzed based on their accuracy, consistency and sensitivity using adjusted-R2, standard error, and regression slope, respectively. The data from all devices and techniques were significantly correlated with feather swatch moisture content (P<0.05). Results from the first experiment suggested potential to measure feather moisture by several of the tested devices. While feather density presented as a challenge during this experiment, it was not considered as a significant issue when evaluating the devices. The “Hay” and “Construction 1” sensors showed the most promise in detecting feather moisture and iv were selected for further testing using live birds. The two devices had relatively higher accuracy, consistency, and sensitivity compared to other devices and techniques. The second experiment (field testing – phase II) evaluated the two selected devices (Hay and Construction 1 sensors) in various commercial broiler settings. Device readings were acquired from the back, wing, and breast feathers. A sample of back feathers from each bird was collected to determine the true moisture. Statistical analyses of data were the same as in experiment 1. Although the initial study, conducted within a lab setting, denoted a significant relationship between true moisture content and device readings, testing within the field environments showed the devices to perform poorly. Readings from both devices and for all the locations tested demonstrated a lack of sensitivity, accuracy, and consistency for measuring moisture in feathers of live birds