Purpose: Detector uniformity is an important parameter in digital mammography to guarantee a level of image quality adequate for early detection of breast cancer. Many problems with digital systems have been determined through the uniformity measurement, primarily as a result of incorrect flat-field calibration and artifacts caused by image receptor defects. The European guidelines suggest a method for the image uniformity assessment based on measurement of Signal-to-Noise ratio (SNR) and Pixel Value (PV) across a uniform image. Nineteen mammography systems from the same manufacturer installed in our organization incorporate an a-Se direct conversion detector. Since their installation, instability and inconsistency of image uniformity has attracted medical physicist attention. A number of different tests have been carried out in order to understand and establish reasons for this instability.
Methods: Three different tests have been performed to evaluate the impact of the heel effect, detector temperature and ghosting on the uniformity images. All the tests are based on the acquisition of uniform images as suggested by the European Guidelines for Quality Assurance in Breast Cancer Screening and Diagnosis.
Results: Results show that an increase in detector temperature produces an increase of SNR and decrease of uniformity. A further decrease of uniformity ranging between 20% and 30% is due to the ghosting while a decrease of about 10% is due the heel effect.
Conclusions: X-ray tube, system geometry and detector have an impact on the system uniformity and an understanding of the contribution of each is necessary in order to obtain comparable image quality among all the systems.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.ejmp.2019.12.021 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Tracking hydrothermal infiltration within light oil reservoirs using organic geochemical proxies in the Shunbei area of Tarim Basin in China.
Sci Rep
January 2025
Northwest Oilfield Company, SINOPEC, Ürümqi, 830011, China.
Deep oil reservoirs are becoming increasingly significant fields of hydrocarbon exploration in recent decades. Hydrothermal fluid flow is deemed as a potentially crucial factor affecting the occurrence of deep oil reservoirs, such as enhancing porosity/permeability of reservoirs, accelerating oil generation and thermal cracking, and modifying organic properties of crude oils. Understanding the interplay between hydrothermal fluids and crude oils would provide useful constraints for reconstructing hydrocarbon accumulation processes and predicting the distribution patterns of crude oils.
View Article and Find Full Text PDFRisk Communication and Community Engagement (RCCE) implementations to control cholera outbreak in Oromia region, Ethiopia.
Trop Med Health
January 2025
School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia.
Background: Oromia regional state experiencing cholera outbreaks in a protracted pattern despite various interventions at local and regional levels. This study aimed to examine the implementation of Risk Communication and Community Engagement (RCCE) activities for cholera outbreak control in the region.
Methods: We conducted a quantitative and qualitative mixed-method study.
Recent developments on aerial lab-on-a-drone platforms for remote environmental monitoring: A review.
Anal Chim Acta
February 2025
Instituto de Química, Universidade Federal de Goiás, 74690-900, Goiânia, GO, Brazil; Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas, 13084-971, SP, Brazil. Electronic address:
Background: Distinct classes of environmental contaminants - such as microplastics, volatile organic compounds, inorganic gases, hormones, pesticides/herbicides, and heavy metals - have been continuously released into the environment from different sources. Anthropogenic activities with unprecedented consequences have impacted soil, surface waters, and the atmosphere. In this scenario, developing sensing materials and analytical platforms for monitoring water and air quality is essential to supporting worldwide environmental control agencies.
View Article and Find Full Text PDFDigital recombinase polymerase amplification chip based on asymmetric contact angle composite interface.
Anal Chim Acta
February 2025
Institute of Microfluidic Chip Development in Biomedical Engineering, College of Information Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China. Electronic address:
Background: Digital recombinase polymerase amplification (dRPA) is an effective tool for the absolute quantification of nucleic acids and the detection of rare mutations. Due to the high viscosity or other physical properties of the reagent, this can compromise the accuracy and reproducibility of detection results, which limits the broader adoption and practical application of this technology. In this study, we developed an asymmetric contact angle digital isothermal detection (ACA-DID) chip and optimized the ACA-DID chip structure to achieve rapid digital recombinase polymerase amplification.
View Article and Find Full Text PDFImmobilization of Glycosyltransferase into a Hydrophilic Metal-organic Framework for Efficient Biosynthesis of Chondroitin Sulfate.
J Biotechnol
January 2025
Analysis and Testing Center, Nanjing Normal University, Nanjing, 210023, China. Electronic address:
Chondroitin sulfate (CS) is a structurally complex anionic polysaccharide widely used in medical, cosmetic and food applications. Enzymatic catalysis is an important strategy for synthesizing CS with uniform chain lengths and well-defined structures. However, the industrial application of glycosyltransferases is hindered by limitations such as low expression yields, poor stability, and challenges in reuse.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!