Experimental study on a reconstruction method to suppress image artifacts for magnetic nanoparticle imaging

Current imaging technologies such as magnetic resonance imaging (MRI). X-ray computed tomography (X-ray CT), and positron emission tomography (PET) are utilized in the medical field. Moreover, a new imaging technology called magnetic particle imaging (MPI) has been proposed, and has attracted attention. This technology can image a distribution of internally administered magnetic nanoparticles (MNPs). In MPI, since a signalgenerated from MNPs is detected directy, high sensitivity and high spatialresoution are expected compared to MRI that uses the same MNPs as a medicalcontract media. In this method, a magnetization response from MNPs from a target region is detected by scanning a local distribution of magnetic field. However, the image blurring and artifacts appear due to the interference of magnetization response generated from the MNPs outside target region, so that image resolution is degraded. We have already proposed a new image reconstruction method that focused on the difference between the waveform of electromotive force generated from a target region and outside region. In this paper, we verified the validity of this proposed method by using the prototype system and numerical experiment considering the prototype system's specifications. As a result, the image artifacts were suppressed, and the image resolution was about 10. 3 mm in numerical experiment. We also indicated that the image artifacts were decreased by 32% compared with conventional method in the experiment with the prototype system. However, since the image resolution was about 12 mm in this experiment, it needed to be more improved. © 2012 Japanese Society for Medical and Biological Engineering.