Novel Magnetic Particle Imaging Device for High-Resolution Brain Imaging

Mitsubishi Electric Corporation, in collaboration with Okayama University and Osaka University's Graduate School of Engineering, has unveiled a magnetic particle imaging device designed for highly sensitive imaging of magnetic particles within an area equivalent to the human brain's size. This innovative device operates at remarkably low frequencies, specifically 1 kHz or less, making it a world-first achievement. The low-frequency operation significantly reduces the size and power requirements of the device's power supply unit. The primary application of this technology is quantifying the accumulation and distribution of amyloid-β, which is linked to Alzheimer's disease.

The magnetic particle imaging device functions by using an alternating magnetic field generated by a coil to induce magnetic signals from magnetic particles introduced into the body. These signals are then used to create three-dimensional images. The sensitivity of signal detection is greatly enhanced with higher-frequency alternating magnetic fields. Current compact devices designed for testing on small animals, such as mice, already available commercially, typically use frequencies of approximately 25 kHz.

A major challenge in applying this technology to humans has been the need for an excessively large power supply unit to drive the much larger coil required for human-scale imaging. Through advancements in electromagnetic technology by Mitsubishi Electric, the three collaborating organizations have developed a method that reduces noise interference during signal detection. This innovation is made possible through precise adjustments to the arrangement of the coils responsible for generating alternating magnetic fields and those used for signal detection. This advancement has paved the way for highly sensitive detection and imaging of magnetic signals within samples equivalent in size to a human brain, even at frequencies as low as 1 kHz or less.

The participating organizations have successfully developed a magnetic particle imaging device capable of imaging areas equivalent in size to the human brain while employing a miniaturized power supply unit, made possible by reducing the imaging frequency. The sensitivity of magnetic signal detection is closely tied to the frequency of the alternating magnetic field. Existing magnetic particle imaging devices designed for small animals operate at high frequencies around 25 kHz. However, scaling up such a device to produce human-sized images while maintaining this frequency would require a significant increase in coil load and power supply capacity. Reducing the frequency of the alternating magnetic field to minimize the power supply size has traditionally resulted in weaker signals from magnetic particles, making them undetectable.

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