Tumor Detection Using Millimeter-Wave Technology: Differentiating Between Benign Lesions and Cancer Tissues

There has recently been considerable interest in detecting and managing different types of cancer by using nonionizing electromagnetic waves. These methods rely on the inherent contrast between the electrical properties of malignant and normal tissues. It has been shown that cancer changes the water content as well as the biochemistry (e.g., metal concentration) of tissues [1]-[3], so it changes dielectric properties. In this regard, microwaves have been used to image breast cancer and lung cancer in the frequency range of 300 MHz-10 GHz [4]-[6]. Compared to microwaves, millimeter waves (mm-waves) (30-300 GHz) have shorter wavelengths and penetrate from 700 um to 1.3mm into the body [7], making them highly effective for sensing pathological changes in the tissue layers of excised organs or different skin layers from which most skin tumors originate [8], [9]. As the frequency increases further (>300 GHz), electromagnetic waves barely penetrate the tissues' surface [10], [11] and therefore have a limited ability to detect early-stage tumors that reside in deeper tissue layers.