A 3-D Finite Difference Time Domain Investigation of Microwave Propagation Through Inhomogeneous Biological Materials.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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This paper extends past analysis of an optimal source distribution around a homogeneous sphere of muscle tissue by using a 3-D finite difference time domain FDTD scenario in which an anatomically correct human head model is irradiated. It first duplicates the analytical solution within an FDTD space using an FDTD computer code developed at Penn State University. This duplication uses a 9.45 cm radius sphere represented in an FDTD space of 2.35 mm cubic cells. FDTD simulations are then performed on four, three, and two layer laminated spheres, designed to provide simple models of a head. Finally, four simulations were performed in FDTD on the human head model developed at Penn State from an MRI scan of an actual human head. The comparison of analytic simulations to the FDTD simulations on a homogeneous sphere showed a pixel by pixel average of 5.34 error between the two with a standard deviation of 7.84. The layered sphere models showed considerable spiking at the two poles along with a small amount of spiking due to the stair-step approximation of the spheres. None of these spikes increased the power beyond that at the surface and hence were not critical. The simulations on a true human head showed improvement in depth due to the low-loss of the bone tissue. This study demonstrates that microwave hyperthermia with good resolution is possible in an anatomically correct head model.
- Electrical and Electronic Equipment
- Medicine and Medical Research
- Radiofrequency Wave Propagation