Purpose: To document a study in shielding a high-sensitivity digital mammography system detector from AC magnetic fields of magnitudes great enough to induce imaging artifacts.
Methods/materials: Preliminary evaluation of AC magnetic fields at a site designated for a digital breast tomosynthesis (DBT) system raised concerns that the magnetic component of electromagnetic interference (EMI) may be great enough to induce imaging artifacts. Subsequent measurements using digital detector arrays from two separate manufacturers verified this concern, and AC magnetic fields were mapped, spatially and temporally, throughout the area of concern. A simple shielding model was developed to elucidate the physics of extremely low-frequency (ELF) EMI shielding and independently verify a commercial group's proposed shielding design and installation. Postshielding measurements were performed to demonstrate that the EMI fields were reduced to acceptable levels.
Results: Preshielding measurements showed AC magnetic fields significantly exceeding manufacturers' tolerances for artifact-free imaging in DBT. Continuous measurements demonstrated that the EMI fields varied significantly over time. Some locations in the room routinely averaged above 30 mG and occasionally exceeded 100 mG. The source was attributed to an adjacent electrical supply room, and temporal changes of the EMI were attributed to variations of the building electrical loads. The proposed shielding primarily consisted of continuous aluminum (6.35 mm thickness) and was installed by a group specializing in electromagnetic field shielding. Postshielding measurements demonstrated that the EMI fields were significantly reduced, generally to less than 0.5 mG, and that the shielding effectively dampened the large variations due to dynamic building electrical loads. Subsequent installation and evaluation of a DBT system revealed no issues with imaging artifacts.
Conclusions: The successful shielding of ELF EMI involves physical principles that are not commonly encountered by medical physicists. Modern high-sensitivity digital detectors may be successfully shielded against imaging artifacts with careful application of these principles.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6036379 | PMC |
| http://dx.doi.org/10.1002/acm2.12366 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Plants will form the basis of artificial ecosystems in space exploration and the creation of bases on other planets. Astrophysical factors, such as ionizing radiation (IR), magnetic fields (MF) and gravity, can significantly affect the growth and development of plants beyond Earth. However, to date, the ways in which these factors influence plants remain largely unexplored.
View Article and Find Full Text PDFRecent Advancements in Localization Technologies for Wireless Capsule Endoscopy: A Technical Review.
Sensors (Basel)
January 2025
Department of Electrical and Computer Systems Engineering, Monash University, Melbourne, VIC 3800, Australia.
Conventional endoscopy is limited in its ability to examine the small bowel and perform long-term monitoring due to the risk of infection and tissue perforation. Wireless Capsule Endoscopy (WCE) is a painless and non-invasive method of examining the body's internal organs using a small camera that is swallowed like a pill. The existing active locomotion technologies do not have a practical localization system to control the capsule's movement within the body.
View Article and Find Full Text PDFMagnetic Induction Phase Difference for Cerebral Hemorrhage Detection.
Sensors (Basel)
December 2024
Department of Biomedical Engineering, Army Medical University, The Third Military Medical University, Chongqing 400038, China.
Magnetic induction phase shift is a promising technology for the detection of cerebral hemorrhage, owing to its nonradioactive, noninvasive, and real-time detection properties. To enhance the detection sensitivity and linearity, a zero-flow sensor was proposed. The uniform primary magnetic field and its counteraction were achieved.
View Article and Find Full Text PDFDiagnosis of Autism Spectrum Disorder (ASD) by Dynamic Functional Connectivity Using GNN-LSTM.
Sensors (Basel)
December 2024
College of Information Science and Engineering, Hunan Normal University, Changsha 410081, China.
Early detection of autism spectrum disorder (ASD) is particularly important given its insidious qualities and the high cost of the diagnostic process. Currently, static functional connectivity studies have achieved significant results in the field of ASD detection. However, with the deepening of clinical research, more and more evidence suggests that dynamic functional connectivity analysis can more comprehensively reveal the complex and variable characteristics of brain networks and their underlying mechanisms, thus providing more solid scientific support for computer-aided diagnosis of ASD.
View Article and Find Full Text PDFA Comparative Analysis of Explainable Artificial Intelligence Models for Electric Field Strength Prediction over Eight European Cities.
Sensors (Basel)
December 2024
2nd Department of Radiology, Medical School, National and Kapodistrian University of Athens, 12462 Athens, Greece.
The widespread propagation of wireless communication devices, from smartphones and tablets to Internet of Things (IoT) systems, has become an integral part of modern life. However, the expansion of wireless technology has also raised public concern about the potential health risks associated with prolonged exposure to electromagnetic fields. Our objective is to determine the optimal machine learning model for constructing electric field strength maps across urban areas, enhancing the field of environmental monitoring with the aid of sensor-based data collection.
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!