In a study published in Biosensors, researchers introduced a non-ionizing, non-invasive, fast-imaging microwave-based system for the early detection of breast cancer. The proposed method demonstrates promising tumor detection capability, even when there is a negligible difference between the healthy and tumoral tissues.
Breast Cancer Overview
Breast cancer is the most commonly diagnosed cancer among women. It is a significant threat to women's health worldwide, with one million women being diagnosed each year.
There has been a significant rise in research efforts in technologies aiming at the early detection of breast cancer.
Current Breast Cancer Detection Technologies and Their Limitations
X-ray mammography is currently the most commonly utilized medical imaging technology for breast cancer detection and screening. However, it has several drawbacks, such as the requirement of painful and uncomfortable breast compression, a high number of false-positive tests, and the use of ionizing radiation.
Other technologies also have significant downsides, such as the high cost of magnetic resonance imaging, which limits its use for early detection, or the requirement for the patient to consume radioactive substances for optimal image formation in positron emission tomography.
Microwave Imaging for Breast Cancer
These drawbacks have motivated researchers to develop new non-invasive, non-ionizing, and economically viable breast cancer detection technologies. Among these technologies, microwave imaging (MWI) is emerging as a viable early breast cancer screening method.
MWI methods are based on detecting electromagnetic waves at microwave frequencies scattering and absorbing as they pass through the various breast tissues, focusing on the remarkable distinction between healthy and cancer tissues.
MWI technology also provides appropriate image depth and spatial resolution for tumor detection, the potential for early diagnosis and detection of tumors in dense breasts, a relatively cheap cost, and shortened processing and image-generation times.
Significance of Electromagnetic Waves in a Non-Invasive Detection Technology
Microwave electromagnetic wave propagation covers the most relevant processes of aqueous and biological systems, enabling the detection, characterization, and monitoring of various events.
The penetration depths of microwave radiations into tissues, ranging from hundreds of microns to a few centimeters, make these methods viable for various biomedical applications.
Moreover, due to the non-invasiveness, non-ionizing capabilities, and dependence of microwave propagation on tissue permeability, microwave methods are ideal for non-invasive medical imaging procedures.
Using Microwave-Based System to Detect Tumors in Breast Phantoms
In this study, researchers developed a microwave medical imaging system for tumor screening and detection. The imaging system includes 16 antennas controlled by a switching network comprised of five high-frequency switches, a feeding and control subsystem, and a computer to automate the data collection and image generation operations.
The entire technology was designed to find and locate tumor phantoms that resemble breast cancer cells. Breast tumor tissues were replicated using appropriate combinations of water and TRITON X-100, a synthetic substance often used in these experiments.
The designed breast phantom replicates tumor detection in dense breasts by matching the electromagnetic scattering and absorption characteristics of actual tissue in breasts with a given density.
Calibration tests using basic and metal cylinders were performed to assess the correct operation of the system and fine-tune the algorithms
The system's detection limitations were evaluated using various tumor phantoms with lower dielectric contrast than breast tissues to emulate the dense-breast cancer detection problem.
Important Findings of the Study
The collected data and images demonstrate the system's capacity to detect and localize various tumor phantoms, including those with volumes as tiny as 1 mL, even for low dielectric constant contrast and even when more than one tumor is present.
Utilizing highly directional antennas and an enhanced medical imaging algorithm (IDAS) enabled the system to identify all tumor phantoms successfully.
A small error was detected in IDAS' images, which might be due to flaws in the border-removal algorithm, or the breast phantom was not centered precisely in the measurement region. However, it does not affect the tumor's detection capability of the proposed system.
Future Developments in Breast Cancer Imaging
A more significant number of reception antennas active simultaneously for each pulse might improve accuracy. Still, it would be at the expense of a more costly system, more complexities, and longer processing times.
An improved spatial position of the tumors might be achieved with the help of the extra information provided by additional antennas, which could also help to increase the accuracy of tumor detection and localization.
Blanco-Angulo, C., Martínez-Lozano, A., GutiérrezMazón, R., Juan, C.G., GarcíaMartínez, H., Arias-Rodríguez, J., Sabater-Navarro, J.M., & ÁvilaNavarro, E. (2022) Non-Invasive Microwave-Based Imaging System for Early Detection of Breast Tumours. Biosensors. https://www.mdpi.com/2079-6374/12/9/752