Development and implementation of a tomographic system for the quantitative reconstruction of magnetic microparticles based on AC biosusceptometry sensors

Micro and nanostructured magnetic materials (MNMMs) are materials with great potential for several biomedical applications, due to their magnetic properties and small size. However, for better targeting process efficiency, techniques capable of detecting, locating and imaging MNMMs within the organism are necessary. Currently there are some techniques available, but with some disadvantages such as high cost, lack of portability, and restrictions for animal experimentation. Thus, Alternating Current Biosusceptometry (ACB) is an alternative biomagnetic technique capable of detecting and performing quantitative imaging of MNMMs in vitro, ex vivo, in vivo, and in real-time. So far, the ACB results presented were restricted to quantitative planar images. To generate quantitative tomographic images using the ACB, we propose an octagonal array of pick-up and excitation coils arranged in an octagonal geometry, enabling acquisition in different projections. This configuration formed by multiple pick-up and excitation coils allowed us to test different methods and setups of coils activation. These different methods and setups enabled a deeper analysis of the ACB inverse problem stability and details. The results showed that the addition of pick-up coils resulted in a better reconstruction due to the amount of information added to the problem. Here we show for the first time the ACB quantitative tomographic reconstruction of magnetic materials distribution.

Automated summary

Micro and nanostructured magnetic materials (MNMMs) have significant potential for biomedical applications due to their magnetic properties and small size. However, techniques for detecting, locating, and imaging MNMMs within the body are necessary for better targeting efficiency. Alternating Current Biosusceptometry (ACB) is proposed as an alternative biomagnetic technique capable of detecting and quantitatively imaging MNMMs in different settings. By adding pick-up coils in an octagonal pattern, it was possible to generate quantitative tomographic images of the distribution of magnetic materials using ACB for the first time.