Detection of brain tumor and localization of a deep brain RF-source using microwave imaging

This paper presents a feasibility study using numerical simulations for microwave imaging based brain tumor detection. An anatomically realistic numerical phantom with a model of brain tumor is used, where scattered electromagnetic signals are generated using the phantom by finite-difference-time-domain (FDTD) simulations. The microwave imaging technique based on Levernberg-Marquadt iterative scheme is used to solve the inverse scattering problem for the head of the phantom in the 403.5 MHz medical radio (MedRadio) band. Two-dimensional quantitative images having the electrical properties of the brain are reconstructed. Differential images are obtained by taking the difference between the reconstructed images with and without the tumor model, and with and without the expected effect of the contrast agents. Although it is difficult to detect a small tumor in the reconstructed image, a tumor of diameter 5 mm can be detected in the differential image in high signal-to-noise ratio (SNR) cases. The simulation results show that at least 45 dB SNR is required for small size tumor detection. Moreover, the paper presents a study of a localization method based on microwave imaging for deep-brain RF-source. The method can be useful for precise positioning of a neuro-endoscope. The simulation results show that it is possible to localize a deep-brain RF-source in two dimensions with a localization accuracy of 5 mm at a SNR of 30 dB.