Modified Solenoid Coil That Efficiently Produces High Amplitude AC Magnetic Fields With Enhanced Uniformity for Biomedical Applications

In this paper, we describe a modified solenoid coil that efficiently generates high amplitude alternating magnetic fields (AMF) having field uniformity (≤10%) within a 125-cm3 volume of interest. Two-dimensional finite element analysis (2D-FEA) was used to design a coil generating a targeted peak AMF amplitude along the coil axis of ~ 100 kA/m (peak-to-peak) at a frequency of 150 kHz while maintaining field uniformity to >; 90% of peak for a specified volume. This field uniformity was realized by forming the turns from cylindrical sections of copper plate and by adding flux concentrating rings to both ends of the coil. Following construction, the field profile along the axes of the coil was measured. An axial peak field value of 95.8 ± 0.4 kA/m was measured with 650 V applied to the coil and was consistent with the calculated results. The region of axial field uniformity, defined as the distance over which field ≥ 90% of peak, was also consistent with the simulated results. We describe the utility of such a device for calorimetric measurement of nanoparticle heating for cancer therapy and for magnetic fluid hyperthermia in small animal models of human cancer.

[1]  P. R. Hannurkar,et al.  Design, fabrication, and characterization of a solenoid system to generate magnetic field for an ECR proton source , 2010 .

[2]  I. Prokhorov,et al.  Dynamic magnetic hysteresis in a liquid suspension of acicular maghemite particles , 2009 .

[3]  Q. Pankhurst,et al.  Corrigendum to “Suitability of commercial colloids for magnetic hyperthermia” [J. Magn. Magn. Mater. 321 (2009) 1509–1513] , 2009 .

[4]  E. Atalar,et al.  Focused RF hyperthermia using magnetic fluids. , 2009, Medical physics.

[5]  A. Mediano,et al.  Adiabatic vs. non-adiabatic determination of specific absorption rate of ferrofluids , 2009 .

[6]  A. Mediano,et al.  Accurate measurement of the specific absorption rate using a suitable adiabatic magnetothermal setup , 2008 .

[7]  Q. Pankhurst,et al.  Size and Concentration Effects on High Frequency Hysteresis of Iron Oxide Nanoparticles , 2007, IEEE Transactions on Magnetics.

[8]  Robert Ivkov,et al.  Synthesis and antibody conjugation of magnetic nanoparticles with improved specific power absorption rates for alternating magnetic field cancer therapy , 2007 .

[9]  Arutselvan Natarajan,et al.  Thermal dosimetry predictive of efficacy of 111In-ChL6 nanoparticle AMF--induced thermoablative therapy for human breast cancer in mice. , 2007, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[10]  Radivoje Popovic,et al.  Microfabricated solenoids and Helmholtz coils for NMR spectroscopy of mammalian cells. , 2007, Lab on a chip.

[11]  B. Jeyadevan,et al.  Heating efficiency of magnetite particles exposed to AC magnetic field , 2007 .

[12]  I. Prokhorov,et al.  Audio-frequency heating of particulate magnetic systems , 2007 .

[13]  Toshiharu Tominaka,et al.  Magnetic field calculation of an infinitely long solenoid , 2006 .

[14]  W. Weitschies,et al.  The effect of field parameters, nanoparticle properties and immobilization on the specific heating power in magnetic particle hyperthermia , 2006 .

[15]  M. Sherar,et al.  Development of a novel loosely wound helical coil for interstitial radiofrequency thermal therapy , 2006, Physics in medicine and biology.

[16]  Kevin R. Minard,et al.  Solonoidal microcoil design: optimizing RF homogeneity and coil dimensions , 2001 .

[17]  G. Popov.  Uniformity and nonuniformity coefficients of the magnetic field produced by a solenoid of arbitrary length , 1998 .

[18]  D.C. Ellinger,et al.  Evaluation of a semi-cylindrical solenoid as an applicator for radio-frequency hyperthermia , 1989, IEEE Transactions on Biomedical Engineering.

[19]  C. Grüttner,et al.  MULTIFUNCTIONAL SUPERPARAMAGNETIC NANOPARTICLES FOR LIFE SCIENCE APPLICATIONS , 2002 .

[20]  P. Wust,et al.  Magnetic Fluid Hyperthermia (MFH) , 1997 .

[21]  B. Paulke,et al.  Preparation and Characterization of Magnetic Nanospheres for in Vivo Application , 1997 .

[22]  P. Stauffer,et al.  Practical induction heating coil designs for clinical hyperthermia with ferromagnetic implants , 1994, IEEE Transactions on Biomedical Engineering.