Magnetic nanoparticle imaging using multiple electron paramagnetic resonance activation sequences

Abstract

Articles you may be interested inDisappearance of electron-hole asymmetry in nanoparticles of N d 1 − x C a x M n O 3 ( x = 0.6 , 0.4 ) : magnetization and electron paramagnetic resonance evidence Improvement of temporal resolution for three-dimensional continuous-wave electron paramagnetic resonance imaging Rev. Sci. Instrum. 79, 123701 (2008); 10.1063/1.3033161 Direct detection and time-locked subsampling applied to pulsed electron paramagnetic resonance imaging Rev. Sci. Instrum. 76, 053709 (2005);Magnetic nanoparticles play an important role in several biomedical applications such as hyperthermia, drug targeting, and disease detection. To realize an effective working of these applications, the spatial distribution of the particles needs to be accurately known, in a noninvasive way. Electron Paramagnetic Resonance (EPR) is a promising and sensitive measurement technique for recovering these distributions. In the conventional approach, EPR is applied with a homogeneous magnetic field. In this paper, we employ different heterogeneous magnetic fields that allow to stabilize the solution of the associated inverse problem and to obtain localized spatial information. A comparison is made between the two approaches and our novel adaptation shows an average increase in reconstruction quality by 5% and is 12 times more robust towards noise. Furthermore, our approach allows to speed up the EPR measurements while still obtaining reconstructions with an improved accuracy and noise robustness compared to homogeneous EPR. V C 2015 AIP Publishing LLC. [http://dx.

Mn-Doping level dependence on the magnetic response of MnxFe3−xO4 ferrite nanoparticles

“…Thus, heterogeneity in size, shape or Mn doping levels would lead to a great broadening effect in EMR signal. 37 The signal broadness is determined by measurung the peak to peak distance (ΔHpp), expressed in Table 2. The similarity between the ΔHpp is related to their similar size distributions and structural homogeneity.…”

Sensor fusion of electron paramagnetic resonance and magnetorelaxometry data for quantitative magnetic nanoparticle imaging

“…( ) changing from measurement to measurement. The approach is detailed in [25,26]. As can be observed from equation (1), it is important to know the response values very accurately.…”

“…The considered virtual EPR-MRX imaging setup is based on an existing MRX setup [19] and EPR setup [26] in order to perform realistic simulations. The external magnetic field is generated by 16 magnetizing coils, each having a diameter of approximately 1 cm and 9 winding turns.…”

“…The external magnetic field is generated by 16 magnetizing coils, each having a diameter of approximately 1 cm and 9 winding turns. The MNP sample, the excitation coil (for generating the radio frequency wave) and the pick-up coil (for measuring the resonance signal), are positioned between 2 groups of 8 coils [26]. The sample is moved through the excitation and pick-up coils.…”

“…Recently, EPR imaging was introduced in which the technique was used to reconstruct the spatial MNP distribution in a sample in 1D [23,24] which was later extended to 3D [25]. The technique was further improved and sped-up by employing magnetic field gradients instead of a homogenous magnetic field [26].…”