(615b) Combined MPI-MFH: A Promising Theranostic Platform

Magnetic particle imaging (MPI)¹ is an emerging molecular imaging technology where imaging signal is provided by the non-linear response of magnetic nanoparticle tracers to a scanned magnetic gradient field. This non-radioactive tracer based technology provides a safer alternative as compared to other radioactive imaging modalities like single photon emission computed tomography (SPECT) and positron emission tomography (PET), and finds application in real-time cardiovascular² and cancer imaging³, cell tracking⁴ and blood coagulation⁵.

Magnetic fluid hyperthermia (MFH)⁶ is a therapeutic approach which uses magnetic nanoparticles to dissipate heat for treating cancer and for drug delivery. However, non-specific uptake of magnetic nanoparticles in MFH can lead to undesired heating in non-targeted organs⁷. To avoid undesired heating of non-targeted organs, the use of the field free region (FFR) concept from MPI provides a promising solution to deliver heat only in the region of interest.^8,9

In this work we utilize the ferrohydrodynamic equations to obtain theoretical predictions of energy deposition by calculating the specific absorption rate (SAR) values and elucidate the effect of MPI field gradient on the spatial distribution of SAR¹⁰. We also demonstrate experimentally the on-demand heating of magnetic nanoparticle vials separated by only 3 mm, using a custom built MPI-MFH setup, along with preliminary results of simultaneous MPI-MFH¹¹. The good qualitative agreement observed between experiments and simulations shows potential of this theranostic technology to serve as the basis of future treatment planning and image guided therapy.

¹ B. Gleich and J. Weizenecker, Nature 435,1214 (2005).

² J. Weizenecker, B. Gleich, J. Rahmer, H. Dahnke, and J. Borgert, Physics in Medicine and Biology 54,L1 (2009).

³ E. Y. Yu, M. Bishop, B. Zheng, R. M. Ferguson, A. P. Khandhar, S. J. Kemp, K. M. Krishnan, P. W. Goodwill, and S. M. Conolly, Nano Letters 17,1648 (2017).

⁴ B. Zheng, M. P. von See, E. Yu, B. Gunel, K. Lu, T. Vazin, D. V. Schaffer, P. W. Goodwill, and S. M. Conolly, Theranostics 6,291 (2016).

⁵ K. Murase, R. Song, and S. Hiratsuka, Applied Physics Letters 104,252409 (2014).

⁶ B. Kozissnik, A. C. Bohorquez, J. Dobson, and C. Rinaldi, International Journal of Hyperthermia 29,706 (2013).

⁷ C. Kut, Y. Zhang, M. Hedayati, H. Zhou, C. Cornejo, D. Bordelon, J. Mihalic, M. Wabler, E. Burghardt, C. Gruettner, A. Geyh, C. Brayton, T. L. Deweese, and R. Ivkov, Nanomedicine 7,1697 (2012).

⁸ K. Murase, H. Takata, Y. Takeuchi, and S. Saito, Physica Medica-European Journal of Medical Physics 29,624 (2013).

⁹ L. M. Bauer, S. F. Situ, M. A. Griswold, and A. C. Samia, Nanoscale (2016).

¹⁰ R. Dhavalikar and C. Rinaldi, Journal of Magnetism and Magnetic Materials 419,267 (2016).

¹¹ D. W. Hensley, Z. W. Tay, R. Dhavalikar, B. Zheng, P. Goodwill, C. Rinaldi, and S. Conolly, Physics in Medicine and Biology 62, 3483 (2017).