Detection of depth of the tumor in microwave imaging using ground penetrating radar algorithm

Abstract

Microwave Imaging (MI) is a new technique for detecting breast cancer using electrical property difference between the non-malignant and malignant tissues present in the breast. Numerous studies show that detecting the depth of the tumor is the essential measure in determining additional management. Developing evidence in many of the literature surveys illustrate that detecting tumor depth is a precise parameter for identifying the affected area. Thus, Ground Penetrating Radar (GPR) algorithm is applied successfully to detect the exact depth of the malignant tissue. Generally, GPR is originally conceived for archaeological investigations, building condition assessment, detection of buried mines, etc. But here an effort has been made to apply GPR to Radar-based breast cancer detection. The simulated bandwidth of the proposed UWB antenna starts at 2.4 GHz and ends at 4.7 GHz. The electromagnetic wave reflected due to dielectric property variation is used by GPR algorithm to identify the depth of the tumor. Before applying a depth migration technique, preprocessing steps like Cartesian form transformation, Hermitian Signal Processing, and Inverse Fast Fourier Transform (IFFT) have to be followed in the backscattered signal to convert positive frequency data into time-domain data. Depth details can be noticed in the migrated image, after applying the migration procedure. Results show that GPR algorithm can be effectively used for detecting the tumor embedded in the depth of the breast tissue. To understand the effectiveness of this imaging scheme, an experimental analysis is done using a combination of wheat flour and water-petroleum jelly. The measured impedance bandwidth of the UWB antenna ranges from 2.8 GHz to 4.48 GHz. The observation is done for a known spherical tumor of diameter 13 mm which is placed at different depths from the skin layer. While applying the algorithm in the received backscattered signal, we were able to detect correctly the tumor at a depth of 45 mm embedded in the breast tissue. The experimental results are compared with simulation ones to validate the aptness of a microwave imaging approach for detecting the depth of the tumor.