Newswise — Imaging techniques, such as computed tomography, magnetic resonance imaging, positron emission tomography, and ultrasound, have become essential tools in the field of medicine. These methods provide invaluable insights into the human body, enabling physicians to not only visualize internal structures with precision but also make informed assessments of defects or functional processes within the body. These imaging modalities have revolutionized medical diagnostics and significantly enhanced the quality of patient care.
A collaborative team of physicists and medical doctors from Julius-Maximilians-Universität Würzburg (JMU) has achieved a significant milestone by making Magnetic Particle Imaging (MPI) viable for human use, offering a radiation-free imaging technology. Led by Professor Volker Behr and Dr. Patrick Vogel from the Institute of Physics at the university, the team has successfully developed a portable scanner. This groundbreaking technology allows for the visualization of dynamic processes within the human body, including blood flow. The promising results of their study have been published in the esteemed journal Nature Scientific Reports.
A sensitive and fast alternative
Magnetic Particle Imaging (MPI) is a technique that revolves around the direct visualization of magnetic nanoparticles, as indicated by its name. These nanoparticles are not naturally present in the human body and need to be administered as markers. Similar to positron emission tomography, which employs radioactive substances as markers, MPI offers the significant advantage of sensitivity and speed without being affected by interfering background signals from tissues or bones, as explained by Volker Behr.
In contrast to positron emission tomography's reliance on detecting gamma rays from a radioactive marker, MPI operates on the response signal of magnetic nanoparticles to varying magnetic fields. "During this process, external magnetic fields are used to selectively manipulate the magnetization of nanoparticles, allowing not only their presence but also their spatial position within the human body to be detected," explains physicist Patrick Vogel, the first author of the publication.
A small scanner for big insights
The concept of MPI is not a recent one. Back in 2005, Philips showcased the first images using this innovative approach in a small demonstrator, which was limited to samples a few centimeters in size. However, developing devices suitable for human examination proved to be more challenging than anticipated, resulting in large, heavy, and costly constructions.
In a significant breakthrough in 2018, the team led by Professor Volker Behr and Patrick Vogel discovered a new method to implement the intricate magnetic fields required for imaging in a much smaller design. Through a multi-year research project supported by the German Research Foundation (DFG), the scientists successfully integrated this novel concept into an MPI scanner (known as interventional Magnetic Particle Imaging - iMPI) explicitly tailored for intervention purposes. This advancement opened up exciting possibilities for more accessible and practical applications of MPI in medical settings.
According to Vogel, "Our iMPI scanner is incredibly compact and lightweight, making it highly portable for use almost anywhere." The authors effectively demonstrated this scanner's mobility through a real-time measurement conducted simultaneously with a specialized X-ray device, the standard tool for angiography in university hospitals. The team, led by Professor Thorsten Bley and Dr. Stefan Herz from the Interventional Radiology Department of Würzburg University Hospital, has been involved in this project from its inception. They performed the measurements on a lifelike vascular phantom and assessed the initial images.
Dr. Stefan Herz, the senior author of the publication, remarked, "This marks an essential initial stride towards radiation-free intervention. MPI holds the potential to revolutionize this field permanently.
Next steps in research
Apart from conducting more thrilling measurements with the iMPI device, the two physicists are currently dedicated to advancing the development of their scanner even further. Their primary objective is to enhance the image quality significantly.
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