Non-Invasive Reflectometry-Based Detection of Melanoma by Piezoelectric Micro-Needle Antenna Sensors

Abstract

Abstract-The electromagnetic characterization of piezoelectric micro-needle antenna sensors for fully non-invasive detection of cancerrelated anomalies of the skin is presented. To this end, a fullwave finite-difference time-domain procedure is adopted to analyze the performance of the considered class of devices in terms of circuital characteristics and near-field radiation properties as a function of the curvature radius of the relevant sensing probe. This analysis is, in turn, useful to gain a physical insight into the processes which affect the behavior of the structure and, hence, the accuracy in the detection of possible malignant lesions of the skin. In particular, by using the mentioned modeling approach, an extensive parametric study is carried out to analyze the effect produced on the sensor response by variations of the complex permittivity of the skin due to the presence of anomalous cells and, in this way, obtain useful discrimination diagrams for the heuristic evaluation of the exposure level to the cancer risk.

Millimeter-Wave Near-Field Probe Designed for High-Resolution Skin Cancer Diagnosis

“…These probes achieve a spatial resolution of several micrometers down to several nanometers; however, their sensing depth is typically also in the range of a few nanometers to micrometers, and therefore they are not suitable for skin cancer diagnosis. Using a small monopol antenna, e.g., an extended inner connector of a coaxial probe, to achieve a higher probe resolution than the waveguide cross section has been suggested for measurements on tissue [28], [29], but the distance of the sharp probe tip to the tissue under test has a large influence on the measurement and might be hard to control in in-vivo measurements. Probes that use a small apertures to confine the electromagnetic fields [30], [31] have an energy transfer to the tissue that is inversely proportional to the aperture size, and therefore a compromise between resolution and sensitivity has to be made depending on the intended application area.…”

Simulation of an Electromagnetic Acoustic Transducer Array by Using Analytical Method and FDTD

“…Due to its advantages of having good penetration depth and mechanical flexibility, the piezoelectric ultrasonic method is widely used for thickness measurement, flaw evaluation, and material characterization [8][9][10][11][12][13]. The transducer frequently used is made of piezoelectric ceramics or crystals [12][13][14][15]. However, one primary disadvantage of the piezoelectric ultrasonic testing is the need to have good sonic contact with the test piece, typically by means of a couplant for acoustic impedance matching [16].…”

Millimeter-Wave Tissue Diagnosis: The Most Promising Fields for Medical Applications

“…The reduction in size of a rectangular waveguide probe is limited by its cutoff frequency. Therefore, researchers have investigated alternative probe designs for tissue sensing, such as tapered waveguides [42], tapered transmission lines [43], [44], micromachined open-ended strip line probes [12], [45], [46], and coaxial lines with an extended inner conductor serving as an antenna [36], [47], [48]. An overview of some alternative miniaturized near-field probe designs for tissue sensing is provided in Table 1.…”

“…An application that triggered big hopes, and that has been investigated by a number of research groups, is the diagnosis of skin cancer [28], [35], [48], [117]. The incidence of malignant melanoma, the most dangerous skin cancer type, is increasing at one of the fastest rates among all cancer types, and the current lifetime risk is nearly 2% for the U.S. population [118].…”