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Magnetic particle imaging (MPI) and magnetic fluid hyperthermia (MFH) have the potential of being integrated in a single device to allow for seamless switching between imaging and therapeutic modes. In an MPI-MFH platform, the field free region of an MPI scanner can serve not only for imaging diagnostics but, by adding a radio-frequency magnetic field, also for therapeutic use of the magnetic particles by heating. It enables precisely localized heating to a specific target temperature deep in the tissue via MFH. In addition, MPI provides targeted visualization and temperature information of systemically injected magnetic nanoparticles providing direct feedback. In this work, the integration process of a hyperthermia insert which is capable of extending a commercial magnetic particle imaging scanner with the functionality of magnetic fluid hyperthermia is presented. Furthermore, the thermal resolution of the MPI-MFH platformis measured., International Journal on Magnetic Particle Imaging IJMPI, Vol 9 No 1 Suppl 1 (2023)

The method of magnetic particle imaging (MPI) is substantially limited by a rather small field of view (FOV) even in preclinical imaging. To cover a bigger FOV, a multi-patch approach – i.e., scanning of a series of small FOVs (patches) shifted in the space - is necessary. Here, we present a simple software tool for merging of patches into a final 3D volume data of the scanned object. The software reads reconstructed data produced by a field-free point scanner (MPI 25/20FF, Bruker BioSpin MRI GmbH, Germany), merges them, averages data overlapped in the space, and export them in DICOM format. The software is free for non-commercial use., International Journal on Magnetic Particle Imaging IJMPI, Vol 9 No 1 Suppl 1 (2023)

This file contains information about the file names and locations for the data used to build figurtes in the manuscript: In situ theranostic platform uniting highly localized magnetic fluid hyperthermia, magnetic particle imaging, and thermometry in 3D # figure 1 - general description # MPI guided MFH. Visualization of the gradient field distribution in space resulting from spatially varying magnetic fields. Only SPION located in the region with the vanishing magnetic strength (field free region, FFR) can interact (imaging, heating, etc.) with additional magnetic influences. FLIR-camera characterization of global heating (selection field OFF) and spatial distribution in a 3D phantom of SPION samples within the FOT distributed over a grid of 16x16mm (in y- and z- direction) surrounding the center of the MPI-MFH platform (x =0). # figure 2 - Determination of field of therapy (FOT) # MFH insert is moved in X-direction equipped with 9 SPION samples (synomag-D-70, 140µl, 10mg/(Fe)/ml). global MFH is applied (P = 600W, two heating cycles 25s) # figure 3 - Determination of MFH-FFR # driving through the MFH insert in every direction around the center with a robot controlled sample holder equipped with SPION sample (synomag-D-70, 27µl, 10mg/(Fe)/ml). local MFH is applied to the MPI-MFH platoforms' center (fixed FFP (x,y,z direction of 1.25 T/m , 1.25 T/m , 2.5 T/m respectively), P = 300W, one heating cycle 30 s) # figure 4- Agarose MFH # Thermal camera monitored extent of temperature change in a SPION-filled petri dish subjected to localized and global MFH. # Localized MFH: # figure 5A-E - comparison of different SPION samples at different concentrations samples were subjected to MFH: P = 600 W, selection field gradient = 1 T/m, 1 T/m, 2 T/m, (x, y, z), 1 heating cycle of duration = 10 s # figure 5F - MPS measurements # folder "MPS_Data" contains the raw MPS measurements (pure devices, drive field = 25mT, excitation frequency = 25kHz) from the different SPION samples (50µl) at their respective stock concentration (see figure 10 (table SPION samples)) # figure 6a - targetted heating in punctiform SPION samples samples were successively subjected to MFH: P = 600 W, selection field gradient = 1 T/m, 1 T/m, 2 T/m, (x, y, z), 1 heating cycle of duration = 10 s # figure 6b - targetted heating in agarose # folder "targetted heating"; subfolder "agarose" MFH targeting in a continuous agarose-SPION suspension. The MFH target describes a circle through the agarose-SPION hydrogel. Spatio-temporal distribution of the maximal temperature on the agarose surface every 3.3 s corroborates a circular MFH trajectory. two lines were drawn through the center of the thermal camera recordings representing the y- and z planes within the MPI-MFH platform. The maxima at distinct timepoints during MFH of those axes were plotted. # thermal camera recordings: subfolder "thermal camera readout" Z_1(-34).csv represents the maximal temperature values of the z- plane Y_1(-34).csv represents the maximal temperature values of the y- plane # pixel size = 0.29 mm # Figure 7 - Interleaved MPI-MFH1 # Three SPION samples at equidistant positions within the MPI-MFH platform (x, z = 0 mm; y = -8, 0, 8 mm form center) were subjected to alternating MPI-MFH sequences. # By adjusting the MFH-FFR, the SPION sample positioned at y= -8 mm, was targeted by MFH while MPI images were acquired of all samples. # The MPI images used for MPI-based thermometry are stored in folder "MPI meausurements" subfolder "E31" (name of measurement) subsubfolder "19" (name of reconstruction) # The multi-contrast reconstruction results are stored in the folder "MPI multi-contrast results". "multi_color_spot1.mat is the MPI signal over time for the SPION sample at y= -8 mm "multi_color_spot2.mat is the MPI signal over time for the SPION sample at y= 0 mm "multi_color_spot3.mat is the MPI signal over time for the SPION sample at y= +8 mm # thermal camera data of SPION samples is stored in the folder "thermal camera readout" Rec138_left.txt is the temperature profile of the SPION sample at y= -8 mm Rec138_mid.txt is the temperature profile of the SPION sample at y= 0 mm Rec138_right.txt is the temperature profile of the SPION sample at y= +8 mm # Figure 8 - Interleaved MPI-MFH2 # Three SPION samples at equidistant positions within the MPI-MFH platform (x, z = 0 mm; y = -8, 0, 8 mm form center) were subjected to alternating MPI-MFH sequences. # By adjusting the MFH-FFR, the SPION samples were targeted successively while the temperature profile was monitored with a thermal camera. # The MPI images used for MPI-based thermometry are stored in folder "MPI meausurements" subfolder "E24" (name of measurement) & subsubfolder "3" (name of reconstruction) # The multi-contrast reconstruction results are stored in the folder "MPI multi-contrast results". E24_values_left.mat # thermal camera data of SPION samples is stored in the folder "thermal camera readout" Rec139_left.txt is the temperature profile of the SPION sample at y= -8 mm Rec139_center.txt is the temperature profile of the SPION sample at y= 0 mm Rec139_right.txt is the temperature profile of the SPION sample at y= +8 mm # figure 9 - dynamic phantom # Effect of MFH in a flow phantom. A flow system connected to a tube filled with SPIONs was placed inside the MPI bore to mimic blood circulation and investigate the effect of circulation velocity on heating efficiency. The circulation phantom was targeted with interleaved MPI and MFH cycles successively heating and imaging the circulating SPION. # folder "dynamic_phantom" # Thermal camera measurements at different flow velocities: Rec261_center.txt # Acquired MPI images were used to reconstruct temperature progression during MFH using the MPI-based multicolor method on the basis of thermal camera measurements. # Folder: "MPI measurements" # MPI measurements used for temperature reconstruction (measurement folder/reconstruction folder): 387/20 # MPI- based multi-contrast results in folder "multi_contrast_results" # figure 10 - table comparison tracer # stored in folder: "tracer comparison/figures/table_tracers"

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