Magnetic Particle Imaging for Quantitative Evaluation of Tumor Response to Magnetic Hyperthermia Treatment Combined with Chemotherapy Using Cisplatin

Abstract

This study was undertaken to evaluate the tumor response to magnetic hyperthermia treatment (MHT) combined with cisplatin (MHT ＋CDDP ) using magnetic particle imaging (MPI). Colon-26 cells were implanted into the backs of mice. When the tumor volume exceeded approximately 100 mm 3 , the mice were divided into control, MHT, CDDP, and MHT＋CDDP groups. In the CDDP and MHT＋CDDP groups, CDDP (5 mg/kg) was injected intraperitoneally. In the MHT＋CDDP group, magnetic nanoparticles ［250 mM (14.0 mg Fe/mL) Resovist ® ］ were directly injected into the tumor one hour after CDDP administration, and MHT was performed for 20 min using an alternating magnetic field. In the MHT group, only MHT was performed after the injection of Resovist ® . In the MHT＋CDDP and MHT groups, MPI images were obtained using our MPI scanner immediately before, immediately after, and 3, 7, and 14 days after MHT. After the MPI studies, we drew a region of interest (ROI) on the tumor in the MPI image and calculated the average and maximum MPI values and the number of pixels within the ROI. In all groups, the relative tumor volume growth (RTVG) was calculated from (V-V 0 ) /V0, where V 0 and V were the tumor volumes immediately before and after treatment, respectively. The RTVG value in the MHT＋CDDP group was significantly lower than that in the MHT group 3 to 14 days after MHT. It was also significantly lower than that in the CDDP group at 4 to 11 days except at 6 and 9 days after treatment. The average and maximum MPI values normalized by those immediately before MHT in the MHT＋CDDP group were significantly higher than those in the MHT group 3 days after MHT. Our results suggested that MPI is useful for quantitatively evaluating tumor response to MHT combined with chemotherapy. magnetic particle imaging, magnetic hyperthermia treatment, magnetic nanoparticles, cisplatin, tumor response

MPI Phantom Study with A High-Performing Multicore Tracer Made by Coprecipitation

“…Both, MPI scanners and tracers are still under development. Regarding tracers, Resovist ® is still a kind of standard for MPI, since most published studies of MPI, especially those obtained by in vivo experiments, have been conducted with this tracer [2,7,8,9,10,11,12,13,14,15,16,17]. Since Resovist ® was initially developed as a contrast agent for MRI of the liver it has some disadvantages when used for MPI.…”

A Novel Therapeutic Strategy Combining Use of Intracellular Magnetic Nanoparticles under an Alternating Magnetic Field and Bleomycin

“…One hour after the injection of HVJ-E/MNPs or both BLM and HVJ-E/MNPs, each mouse was placed in a holder and set in the coil for generating an AMF [24]. This coil consists of 19-turned loops (6.5 cm in diameter and 10 cm in length) of copper pipe (5 mm in diameter) and is cooled with water to ensure constant temperature and impedance.…”